You might want to think about running 4 total offensive units - one made up of your best 11 offensive players, and 3 units where you have back ups. With 35, my guess is those back up units will have maybe 5 kids you're getting plays for, with 6 starters. If you mix it up right, and play around with formations and a shorter play book for those groups (to maximize their reps and increase execution), you'll move the ball. I run 3 total units on O, two with back ups. That's 16 plays with my 8 play MPR (30 kids). You'd need 18 plays for 3 similar units. If you can speed up the pace of your entire offense, that's not a bad scenario. Especially considering your D is stacked, so you'll get the ball back.
The way I work it - I run in a back up group, run a 3-4 play series no huddle, and they stay in while they move the ball. If they run into a down and distance issue (2nd and more than 10, 3rd and 5+, 4th and more than inches), then I run my best group out to get the first down. Then back in goes one of my back up groups once we get the first down.
Personally, with 35 I'd probably give the D first choice of 11, then I'd pick the best offense. Usually, I can find 4-5 players that aren't starting on D to be on the starting O and not give up much if anything. Then give the D the next best 5 or 6 kids for subs. Then I put the rest of the kids on offense. I try not to use the defensive subs on O unless they are of "starter" quality, or they're giving a starter a needed rest.
If you run two back up offenses and mix in 5 subs, that's 10 kids you're getting plays for. If you run 3 mixing in 6 starters, that's 15 - and that should do it.
I'd use a different play package for each group, and/or different formations. With the no huddle, that makes it hard to scout and prepare for you.