I like that cooling plate. Seems like the way to go for immersion cooling.
My chiller is a Perlick 4204PRUL. It draws around 5 amps for the compressor and has a 5 gallon reservoir. When I wrapped the copper, I used ratchet straps with a strong spring attached to crank it tight then went around it with a rubber mallet, making the tube slightly ovoid in spots.
Afterwards, I silicone caulked where the tube met the stainless. After some research I decided silicone conducted better than air and would help keep it tight. I do like dray's idea with the copper wool. Oh and the day before, I used jb weld to anchor the start of the coil, which helped. The project wasn't too hard, a full day with a buddy helping.
I think my problem with keeping it cool was due, largely, to the tank being uninsulated. My intention was to eventually have ambient temps keep the tank cold, so I figured that would be easier without insulation. I thought the chiller would have no problems, but apparently it struggled.
Now, however, the tank is covered in spray foam and I think my problem with keeping cool will be gone. I'll find out here in a week or so when my moto is ready.