Hey @silverstackeruk, you are experiencing the 'stackers dilemma'. I think we have all gone through it at some stage in our stacking journey.
My head says I should be stacking low premium high oz silver bars. They are easy to liquidate, super easy to store and a bit of tarnish give them character.
My heart says I should stack what I enjoy and that which gives me pleasure.
The outcome, I have a hybrid strategy. About 75% of my stack consists of bars, rounds and rounds at relatively low premium. The other 25% is my pleasure stack... numismatic coins, collector series, proof coins, unique finds, etc.
I actually get as much pleasure from both, but the future plan if required is to liquidate the lower premium and hold the collectables.