I know this is not optimal but because of kids/wife/clutter I want to put these under the window seats to the sides of the tv. This would also mean putting them on their sides.

Of course I would do cabinet cut-outs and cover with speaker cloth but are there any suggestions on how best to do this?

i.e. push them to front of cabinet? center them? push to back? lay on bottom? prop off the bottom?

Denon x4500h
ADA-1000 x3
VP160HP
M5HP x2
M3OW x2 sides
M2OW x2 rears
M3 In-Ceiling x4