monitor series speaker placement for 5.1/7.1 or atmos

I have monitor t90e fronts, cs2 center and a pair of monitor 40s and r150's
would the 40's work for surrounds and the 150's for rears? the 40's seem kinda big and the
right on would have to be close to a wall. wondering where most people place these and
what I should pair with them in different setups plus what economical ceiling speakers
would work with these for atmos