Did some research and can't find an answer. If I have 2 different config.plists in my EFI, can I choose which one to boot from? and how? basically I want one to be the one I know works without problems, and the other file to be one I can mess with setting to try and get things running or fix problems
You can just save the experimental file with a different name, like: "configE.plist"
When you get to the Clover boot screen/gui, go to options, and there is an obvious place to specify a different config file. I say obvious, because it should/will likely have the default choice already entered "config.plist." In any case, change that to the name of your experimental version, say, "configE.plist" and hit enter. Then go back out to the Clover boot screen and boot your computer!
One of the many nice, in-built features of Clover!
As for GB's suggestion to experiment using a USB drive, that seems more dangerous to me, or at least requires extra USB drives, since it's nice to keep your initial, working USB drive as a last-resort way to save yourself if you really hose your system.
It's possible I'm missing something that GB knows about, but booting from experimental config.plists works for me as I tinker with framebuffer/connection patching to get my R9 290 working. And it saves having to plug/unplug a usb drive, or mess with a USB drive I want to be more universally bootable rather than very specifically configured for max performance.