Probably about 6W as they are fairly efficient (I think the Diamonds must be about 92dB on the usual scale, the Alnicos are 90dB) but that is not the point. I might try a huge muscle amp because reasons.
The original plan was to get a Moon pwr and an AR Ref 5SE (or Ref 6 SE if I can find one) and create a version of the Scalford 2016 system comprised of the bits that Rudi and I brought. The Rank Monos I got from @horace are quite nice but it looks like it is time for a change…
Unfortunately that is the amplifier of choice for the muffin-munching, Astra-driving plutocrats amongst us. Alas, I can only dream of having that much wodge…