I agree re a smaller gtr amp, - a 100w tube Marshall thru a matching 412 cab will cut you in half at 2 on the dial.
But, if it's staying, & he can keep the volume control at 1- you'll be fine.
I used an Ampeg (all tube) V4BH(100w) into an Ampeg 810 cab & I was easily drowned out-at "2" on the Marshall.
Ain't no way I'm gonna REHEARSE at that level again.
Can you add an extension speaker to that combo? Another 15" would be nice
But, if it's staying, & he can keep the volume control at 1- you'll be fine.
I used an Ampeg (all tube) V4BH(100w) into an Ampeg 810 cab & I was easily drowned out-at "2" on the Marshall.
Ain't no way I'm gonna REHEARSE at that level again.
Can you add an extension speaker to that combo? Another 15" would be nice