and hopefully can make more than just one big catch.

Two numbers are assigned to the personnel grouping, first number indicates number of running backs, second number indicates number of TEs.

Hence, 10 personnel is 1 back, 0 TEs, so a 4 WR set.

11 personnel, which texas spends the majority of their time in, is 1 back, 1 TE, so your typical 1 TE, 3 WR set.

21 personnel = 2 backs, 1 TE, or texas’ I-formation.

zero personnel = no backs, no TEs, so 5 WR set, or empty set.

22/13 personnel = 2 backs, 2 TEs or 1 backs, 3 TEs
There are basically your power formation/short yardage/goal line sets.

I think we need to define what a spread offense is and what a West Coast Offense (WCO) is.

My definition of a spread offense is an offense which splits out its players horizontally across the formation (usually putting the offensive linemen in wide splits) in order to increase the seams in the defense, and force the defense to cover the whole field. The purpose of the spread is to force the defense to cover every offensive skill position player, banking on the fact that most defenses won’t have the talent to cover all four of your WRs and your RB, so there is a mismatch somewhere that you can exploit. Spread offenses operate almost exclusively out of 10 or 0 personnel, although you will see some pure spread option teams (ala West Virginia, A&M under Fran) or spread single wing teams (Florida) utilize 12 and even 13 personnel. Pure spread teams do not field a TE on their roster (and calling a big inside receiver a TE ala Missouri doesn’t count), nor do they field a FB (Louisville inder Petrino featured a powerback in their attack known as the S-back, or Superback, but we’re still talking 10 personnel here).
A spread offense will operate almost exclusively out of the shotgun (which texas does), and will normally utilize the zone read as part of its running game (which texas does). However, any team which uses 10 personnel often is going to use the zone read in its running game simply b/c it is an effective one-back running series, so this does not make a team running zone read a spread team.
Now, Wikipedia lists texas as a spread offense. However, it should be noted that whoever wrote that entry for the Spread Offense makes many mistakes, including confusing the spread and run-n-shoot offense (two different schemes with different rules), and giving credit for the invention of the run-n-shoot offense to Mouse Davis when credit is normally given to Glenn “Tiger” Ellison. The author of this Wiki entry credits Ellison with inventing the spread offense, when the truth is, Leo “Dutch” Meyer of TCU invented the first modern spread offense. Given that this person thinks the spread offense is basically any offense using 4 WRs in a formation to spread out the defense, I’m not inclined to take his classification of texas as a spread team seriously (he also neglects to mention Wake Forest or Texas A&M on his list, both of whom are/were pure spread option teams).

Now, my definition of a West Coast Offense is an offense which uses a short passing game and the running game to move the ball down the field, utilizing 3 WRs, the TE, and the RB, i.e. 11 personnel, to move the ball. A WCO will use the passing concepts of Sid Gilman/Don Coryell or Bill Walsh to move the ball through the air. A WCO will use the FB and TE in the running game and passing game, as both blockers and a receivers. WCO teams will usually use 3 number combinations to tell the receivers what routes to run. WCO teams will often utilize 11 personnel and 21 personnel almost exclusively, with some 10 personnel and 22 personnel used in certain situations (short yardage or end-of-quarter/half, for example). The combination routes WRs run in a WCO tend to try to stretch the defense triangularly (pr, in the case of Norm Chow/LaVell Edwards, trapezoidally).
Now, texas’ passing game is based on Sid Gilman and Don Coryell’s concepts. texas tries to get triangular stretches by stressing the Sam backer and strong safety on most route combinations. One of the main goals of the texas passing offense is to force the strong safety to make a decision, and whatever his decision is, he is wrong.
Let’s take a look at a play so you can see what I mean. Here is Right Trips 133 Go. In texas’ offense, the TE (Y) decides the alignment of the formation, so Right means Y aligns to the right side. Y, Z, and B are all aligned on the right side, so we have Rt Trips. The route calls start opposite the TE, so X runs a 1 route, Y runs a 3, Z runs a 3, and B will always have the concept route, which is GO in this case.
Now, look at the defense.
Sam has to cover the TE. If he blitzes or floats into the flat to cover Z, the TE is roaming free for a reception. If Sam covers Y, the SS is forced to cover Z. The problem is, B has a GO route. If the CB presses B, he will get beat deep, and the result is a huge gain. Knowing this, the SS will be tempted to drop to cover deep on B, which leaves Z uncovered for a reception. If the CB backs off and plays zone, B will run his route into the cusion, and turn around to catch a short pass for the guaranteed gain. Whether the SS decides to cover Z, leaving the CB in one-on-one coverage with B, and open to a huge gain, or decides to help B, leaving Z uncovered, he is wrong either way.
This is the essence of texas’ offense, where they are stressing the Sam backer and SS on the play with their route combination. This is basic Sid Gilman/WCO stuff, not spread football.
Now, another difference between spread offenses and WCO schemes is that most spread coaches I’ve talked to are looking for the weakness to exploit, so they can take advantage for the big play and score. The WCO coaches I’ve talked to are generally more of the approach that “this will give us 8 yard here, and we’ll take that every time”. Now, we’re talking about a difference in approaches, of attacking for big plays approach versus the conservative take-what-we-can-get approach, which will differ from coach to coach, but it is just something I’ve noticed among coaches who utilize the two schemes. I think it is safe to say we all know what approach Greg Davis falls into.
Given what I know about texas’ offensive scheme, I think y’all are definitely a WCO scheme, and not a “version of a spread offense”.