As far as I know, Brian's Tri-Sonics, which were from the 60s, were lower output than the later, hotter, Tri-Sonics. Also, AFAIK, the original pickups were fairly flat in their frequency response, without any distinct spikes or dips in the output, so Mother's Milk pickups might suit better than the Slowhands. I'm guessing a bit, although I'll be installing one of each of those pickups in a guitar today or tomorrow.