1) Get yourself a back wash hose and run it to a drain! Get the GOOD stuff--it's like a thick, transparent blue poly and goes on a 2" fitting. Not the cheapo opaque vinyl stuff that goes on 1.5". That solves your problem. I run about 60 ' and have a reel to wind it in on.

2) I don't know the exact level but it will be lower than the Best Guess table. Your manual may have suggested levels for each CYA level. Until you know for SURE, I'd suggest you keep FC at the MINIMUM level for your level of CYA--check the Best Guess table. It's possible to run at lower levels because the chlorine addition is more constant so even if there's a sudden drop due to a bird pooping in it, your SWG will compensate by keeping the level of chlorine constant anyway--or that's the theory....I'll let the experts kick in from here...