Compounding pewter?

[Calderis he/him]

I think pewter would absolutely allow you to store more, and burning A-pewter while tapping would do all the things that A-pewter does (to a slightly lesser degree due to the same power spread over a larger body, opposite what it did for Vin) 

But at that point, just compound to fill a metalmind, then tap and burn A-pewter.