In no particular order:
1. Pick day(s) and time(s) (taking into account the heat of course) when the likelihood of semi-auto shooters is low(er).
2. As someone already posted: a wide brim hat is a must. (E.g., the kind landscape laborers wear is a good choice.) Wear a long sleeve, collared shirt.
3. Pay for two benches (if permitted)--put your gear on the bench to your left while you're shooting.
4. Given the cost of ammo, I've noticed the semi-auto guys dump a few mags and they're done. So maybe you could sit on the sidelines until they've finished.
5a. If you're injured by flying brass, inform the RSO--he's obligated to complete an incident report. Ask for first aid! Take a photo of the burn, too.
5b. Ask for a copy of the Range's Standard Operating Procedure. You're looking for safety guidelines, incident reporting, etc. and the RSO's obligations for a safe environment. The SOP should have the contact information for the Responsible Person--contact them.
5c. Contact their insurance company and speak to the person who handles the account. Make them aware of the issues.
6. Make one of these and bring it with you; when the guy to your left is shooting a semi-auto, clamp it to his bench top:
Brass Catcher -- it's see-through, so it won't obstruct the RSO's (or anyone else's) view.