Ok, I've done testing on Tribble, and now Holodeck, with a couple of my characters, including those with and without Power enhancing traits, various ranks/skill levels, and ships/devices. I'm fairly confident this is a workable Unified Power Formula:
WCE = Warp Core Efficiency
WCP = Warp Core Potential
XP = Subsystem X Performance
I have started revamping the spreadsheet, and hope to have it completed and posted in the next couple days.