If interested, here is something from Ian Boyd on Ash and schemes
The schematic choices ahead for Chris Ash - Inside Texas
" .... Against Utah and their multi-TE formations, the Longhorns had a few measures for stuffing the Utes. The main issue was the perimeter, where Utah had zone-read keepers, outside zone plays, tight ends, and sweeps to utilize in order to command attention and create creases inside for RB Zack Moss. Inside, Texas had Keondre Coburn and Ta’Quon Graham, making those gaps a less appealing target if they could avoid getting swamped on the edge. Playing Ossai on the edge was helpful in avoiding that, as was a 3-4 package Texas created for this game in which Ossai played opposite Malcolm Roach in the other OLB spot. They owned either edge against Utah’s bigger sets.
Texas won’t face many teams in 2020 that try to attack them like the Utes did. However, there will be carry-over from the 2019 Alamo Bowl in that Ossai and the Texas DL will play a big role in setting the edge from four-down fronts. The next big question beyond that is how the Longhorns can play to their strengths up front in the overall defensive structure.
4-3 press quarters vs 4-2-5 press quarters
Up until now, Chris Ash has almost always run a 4-3 press quarters scheme. In limited talks with his new charges that have leaked out we’ve heard the phrase “4-2-5 press quarters.” I don’t know precisely what Ash means by that but I do know what tends to differentiate these two schemes.
Ash’s 4-3 is built out of the “Under front” that plays the strongside DE and nose tackle to the wide side of the field with the middle linebacker and is designed to regularly receive help off the edge from a split out sam linebacker.
That doesn’t really work out so well in the Big 12 though. Playing a linebacker at sam, however mobile he might be, creates serious limitations when teams get into “trips” sets and he’s carried way outside of the box. If you don’t want him carrying verticals by slot receivers then you have to leave your backside cornerback in man coverage with very little help from the safety...."
Lots more at the link