I bought myself my first proof coin recently which was a 5 oz Libertad.

The premium was not too high but still higher than I would like.

I maybe will try to flip it even I think the price might not appricate this much and I dont mind holding it till I die as it looks great.

I would check the secondary market for previous proof sets and look if you can sell them easily without a loss and you can still put that in bu coins if you so choose.