My opinion and experiences only... The Quad 606mk2 onwards *to me,* is a true now lower cost safe-as-houses reference point, able to drive well over 200W per channel into a 4 ohm load and able to drive practically anything within reason, including electrostatics - all this without losing the music in my experience! The 606mk1 needs the larger supply caps at least (when new, the mk1 could sound grainy/dirty for the first hour or so, not the later ones I remember, which came on song practically after switch-on). Preamp choice will be important though. I think it's happy with a passive, but active preamps can often have more of a sonic influence than the power amp itself, so choose carefully is my recommendation. I seem to think a current Croft Micro 25 would be a great start myself.
Of course there are other power amps out there and some have ballistic bass while others have etched 'detailed' highs. Trying to find a nice balance all through while safe into a possibly tricky electrostatic load may well be a problem, especially if you made the speakers yourself. I'm sorry I can't help any more.
Depending on the efficiency of the speakers, I wonder how the neat Quad Vena II would do? Looks great in the flesh and 'feels' right as well imo... price isn't high either.
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