@ecpninja if you are more use to the type of drive your Meitner MTR-101 mono amps have now, and even though your speakers spec is 8ohm / 92db sensitivity, the room size and desired volume listening levels is a real factor to consider.
Coming from your existing SS Mosfet amps, I could see why Will Vincent might lean you towards Mono amps instead of the ST70 stereo amp build he does.
If you go with Quicksilver and want more Transformer capability and drive, the Mono 60s, Monos 120s, or the latest QS Monos in order to run a wider array of output tubes ranging from low to higher power ranges, and different sound types.