Tube amp for Magnepan 3.5 with autoformers.

I just purchased a set of 3.5s and am using a Plinius 9200. I would like to get a tube amp but know Maggies need alot of power. I am considering Speltz autoformers. Any sugesstions? I don't know how much power I will need with the autoformers. Am I better off without the autoformers as I have no experience with them? My budget is under $2500 used. I listen to mainly accoustic, female vocals, and jazz but do listen to some rock and classical. My room is 17 x 28. Would I be better off with a tube pre and a ss amp? I know there are alot of threads on Maggies and amps but would like to hear some fresh ideas.

Thanks, Pal.