My "dream" system is bi-amped, and most of my breadboard experiments have leaned to that end. If you have a good sized listening room, then you can go with lotsa watts. For the bass - SS is OK, but PP tube amp in UL mode with god damping is way better in my opinion. Shoot for 50W/ch. For the mid section, 5 to 20 W/ch will work, shoot for 10 or more. The tweeter does not need much but still need to have plenty of head room, try for no less than 3W/ch.
Harmonics is an important consideration. 2nd harmonics on the mids and tweeter is essential in my opinion, and bi/tri-amping lets you take advantage of that. SE-UL for the mids is a good choice. The JE Labs EL34 is perfect, although in UL you lose some of the 2nds and pick up some 3rds. I'm building one similar myself, but mine will be an ambiance amp for small full range side speakers. Mo-beta is 300B SET and crank it. Shoot for 10-12W/ch with top of the line OPT. The mid is actually the most important octave ranges for conveying the essence of the music, so don't scrimp there. And you need plenty of headroom, so more watts is better. The 300B is the quintessential SET, my bi-amp system will use 300B SET for the mid/highs.
For your tweeters, just about any tube run in SE triode strapped mode will give you those oh-so-sweet 2nd harmonics. I've had success with 6BM8, EL84, 6V6, 6AV5, 1626, but I'd lean toward an EL34 SE triode strapped. Look for the "sweet spot" as you'll get all the watts you need regardless.
Sounds like you have your drivers, so pick the frequency ranges/crossovers to suit the drivers. If you have a clean sheet, I'd suggest the bass run the first 3 octaves, the mids carry the middle 4, and the tweeters blow the top 3.
If you google around, you can find some info on how many watts are required for good balance depending on where the crossovers are. Try Elliot, Mapletree....
You've got a great project ahead of you