Running JFET drives at higher voltages?

jeztone2

I've just revamped my board to include a Boss MS-3. My mainstay drive, the Goosoniqueworx 7thvn, is designed to run at 12 volts. But as I can't switch it's channels remotely. I've replaced it with a Catalinbread DLS for medium gain and a Friedman BE-OD for high gain settings. As they were the most similar pedals in voicing.

Both pedals can be tun from 9-18 volts. But so far, I'm not getting anything more out of the Friedman at 18 volt. Whereas the DLS sounds better at 12 volts. I was hoping for more bottom end. But I'm thinking 12 volts might be the best compromise? 

Anyone else doing this? What were your findings?