I'm trying power my GH2 with a DMW-DCC8 DC coupler on the 7.4v dc jack on my Fotga DP500II V-Mount power supply. I'm having a little bit of trouble trying to find the right cable to connect the two. Does anyone have any specs on the size of either of these jacks or any solutions?

No, but be careful if you have adjustable settings on the unit. I set the wrong voltage on a unit and fried the circuit board of a GH2, luckily Panasonic was able to repair quickly. Sold all of the gear so I can't help you now, sorry.

Good luck with finding the cord you need.