I agree with @ghdprentice . You are all over the map You have gone from 25wpc to 250wpc and from 97db floor standers to 85db bookshelf speakers. You are trying to fill a big room but that won't be done with bookshelf speakers. Changing amps isn't going to change that fact.
I too have a big room which is also my LR, & DR which is 15 x 32. I fill it with a 65wpc Don Sachs Kootenay and Silverline speakers with subs..Before that an ST-70 w/ 35wpc. FWIW Don Sachs also has worked with Spatial audio and has their speakers