What's your ensemble classification? If it's anything non-varsity, then cut the part that has the least amount of playing and get your kids playing as much as possible. If possible, try to have students cover crucial parts that you cut on other instruments (ex. a bass drum player playing a crash during rest).

If you are a Varsity group, your judges might be a bit more picky, so I would really try to cover as much as you can. Divide up the least busy part and have everyone cover it as much as you can. Doing what you said with crash on a sus is a great way to do that kind of thing.

Don't pull a wind player. You are not playing at carnegie hall. It's not that big of a deal to leave some things out.