There's a floor stand for the QS8. Maybe use that in front of the curtain?

Re 7.1 vs 5.1 there are many opinions on this. One factor is how much music vs HT. Generally 7.1 would benefit HT more than music, as there is no discrete 7.1 music.

This is just my opinion, but I'd recommend a 5.1 config with an EP500 over a 7.1 with an EP350. Reason: I love bass, and you appreciate that on both HT and music. Room layout is tricky for 7.1 (as you're finding out). Others have different opinions.