Firstly, plan big GTG with a number of our Members and ask them to bring their favourite amplifier to try on the "particular set of speakers" we had a few to try, Nelson Pass, valve, single end Triode, Consumer Crappers and 3 x XXXXXX's which was really cool.
Listen to all the amplifiers and designate which one performs best, which in this case was a very lovely souped up XXXXXX 100w x 2 and everyone fairly well agreed to the outcomes over a full day and a half of tinkering, eating and beers. Try also 3 other amplifiers in the same class as the XXXXXX, in higher wattage class discovering additional power no advantage, to dis advantage actually
Then reaserarch more with the XXXXXX and try a number of transformers at slightly differing voltage output character and Brand, completing a bias/dc offset commissioning routine at every TX swap as you do if you build amplifiers and totally understand "what the heck you are doing"
Continue the tests over many hours and have a good local Mate present to bounce ideas off and try for unbiased evaluation.
Finalise 100w x 2 XXXXXX Amplifier as a Customised match for the Speakers..........
Get 6 pack, invite Mate for dinner, enjoy