If anyone has the Ernie Ball 2204 Nickle Wound Custom Gauge strings, could you tell me if they're ONLY good for low tunings, or if I could still use them in E Standard?
Depends on the guitar.
You may need to make adjustments for that heavy a string.
I have an Epiphone Les Paul Studio.
There'll be way too much tension in standard. Go for a lighter gauge like 11's.