Osiris13,
I too am looking to put my HS20 on a 110" screen and found that about 16' back from the screen got me in the middle to low zoom range and if I am thinking correctly that is the optimal place to set your zoom.
It will be a few more months before I get my HT completed as I am still building the house around it(lol) but I would love to hear how your situation works out.
Kery
ps....Has the HS20 met your expectations so far?