I am also running the BHT with the Adaptto Mini-E. My battery is a LiFePo4 of 52V and I can max out the current settings without fear of overheating the motor or the controller, except if I hold the throttle wide open for a long time at high speed.
It works relatively well but the starts are always somewhat sudden, even if you open the throttle very slowly. The Adaptto hasn't been made for mid-drives, obviously.
Of course, it can be programmed to automatically slow the rate of increase of current, or the rate of increase of RPM, but then you're stuck with the delay when you NEED instant acceleration. I ride very rough terrain and exact control of the throttle IS VERY important.
The BHT is not silent with the Adaptto, but it's not bad. It would also be better with 60 Volts than 52V.
I'm pretty sure that the BHTs that have been available for sale were production rejects. Mine was FULL of steel shavings, making a racket when I turned the shaft, so I had to dissassemble it to clean it up. I also changed the output bearing because it was rough (read: Chinese cheapest).
When I contacted the seller a few months ago, he told me that he had no idea when the motors would be back in stock.