Yeah, the math makes sense, but sadly, I will have to do the upgrade incrementally. I can see going to 600 W. So, maybe an Ameritron amp and an MFJ tuner.
The palstar tuners are way better than MFJunks, but a 989C will work OK if you can pick one up on the cheap and you ground it well.
The only ameritron experience I had was with an AL80B. If you get one of those things, try to find someone to help you mod it to make the bias "always on when keyed" because the automatic bias circuit in the thing sucks and creates tons of splatter/chop in the signal. After I had my amp tech mod it, one of the things I liked about it was it was pretty quiet in operation, and the 3-500ZG tubes are pretty durable.
Sadly, I wish I could remember what he did to the thing but the mod took him like 5 minutes, I think he removed a leg of a transistor or something trivial like that so the bias sensor would just think there was always enough input signal. It makes the amp run -slightly- hotter but its not even worth worrying about, I don't even know why the
**** MFJ put it in the design to begin with....
FWIW there is a yahoo group called AMPS that's an email list, if its still around I would subscribe to it. BTW the smartest guy on there is Rich Measures, by orders of magnitude. He has a wacky sense of humor but he knows more about tube amps than most people have forgotten.
ETA: If you pick up a DC based amp and you need a stupidly large power supply to run it, I have a PowerTen rackmount supply in my basement you could borrow indefinitely... I am pretty sure it still works but I'd have to test it. 220 vac input, though.. but does 0-20 VDC out at 100A. All I know is it cost somebody like 3 grand back in 2000? or so...
-Mike