Personally I tend to think of:
MSA/IFR
MSA/VFR
500MSD
Each of which is reasonably straightforward to understand as a concept, and for most VFR nav, MSA/VFR = MSA/IFR-500ft, generally is a sensible minimum. It has no legal force of course, but that doesn't stop it being workable and sensible.
If dodging to stay VFR below cloud, or having fun low level, then it's 500MSD, but done at one's peril!
G