@Chad Given the phasey weird effects that you use, I really think that the best amp for you would be the Orange Rocker 32 even though it's a little more than your initial budget.
https://www.sweetwater.com/store/de...rocker-32-30-watt-2x10-inch-stereo-tube-combo
It is basically two of the Tube driven Rocker 15's in a single cabinet with a pair of 10" speakers. The stereo effects return would take your ambient and delay sounds to a new level.
EDIT: Sorry I didn't read all 4 pages first. If the Marshall doesn't work out, consider the Orange 32.