For my universal PSU (GRLV + GRHV), I use a Galaxy 3U chassis which comfortably accommodates the 680uf/550V capacitors. The chassis has no true finned heatsink, it has what the vendor calls the "quasi heatsink".
I use this PSU to power my Carbon, Blue Hawaii, Grounded Grid and the CFA. I bolted the transistors of the GRHV to a L angle which is then bolted to the "quasi heatsink". Even powering the Blue Hawaii, which draws much more current than the Carbon does, the "quasi heatsink" only glows warm to the touch.
I believe even if you just bolt the GRHV transistors to t