Are the parts there?
Are the parts balanced?
Are they making characteristic sounds?
Look for things with unison bass lines and no more that two trumpet/clarinet parts.
Upper sounds will have to work harder to balance to lower sounds. Lower sounds will have to work harder to provide a bigger foundation for the upper sounds to fit to.
If you have the kids, see if anyone is interested in playing tenor/bari/bass clarinet for UIL to help out.
Sight reading is a different story. Prepare your kids as best as you can but realize that SR is a crap shoot at best, even for full groups.
The 3rd group at high school SE of Houston has made ones on stage the last two years with less than 20 winds. One of those years they made ones in sight reading also.
It can be done, but takes a director that can pull every ounce of effort from the kids and isn't afraid to stress fundamentals and good musicianship on attainable music rather than let their ego take control on a more difficult concert.