32GB RAM Mainstage?

I am looking at a new Mac for Mainstage / Logic use.

My question is whether its really worth getting 32BG RAM just because its available - will it make much of an improvement to typical Mainstage use?

Same goes for the 6 and 8 core units? Where would I see an improvement?

I was even considering buy a 2015 MBP from the refurb store so I can avoid the dongle situation - these obviously don't have the option of the above specs, but they are a great machine all the same.

thanks