mtg cards like all that glitters - The List Reprints All cards will be carefully packed for safe transit All That Glitters : r/mtgaltered

10-12 MIGHT BE MORE REASONABLE A common number that people report having built is 10-12

2021-03-19 You are never forced to activate mana abilities to pay costs, so if there is a mandatory additional mana cost (such as from Thalia, Guardian of Thraben), you can decline to activate mana abilities to pay for it and hence fail to cast the suspended card, leaving it in exile

However, getting it later seems like a bit of a liability

Discerning Financier For the variant on Land Tax alone, Discerning Financier can be a useful Commander card

Just from that base case, it should be pretty obvious that this can get ridiculous rather quickly, especially if you are sacrificing creatures yourself - like tokens dragons - and you can give it haste to swing the step it enters