A cap is just a cap. In this application. Really. There is no special magic, and obviously the cheaper the better, as long as they are good. And store energy reliably.

BTW, other things can also do that nowadays, maybe better, and might be worth looking at.

Whether 100 uF is the right value, I don’t know, but it is a nice round number.

Bye the way, Flashy Mike has just posted some OTSM code that looks interesting. It is beyond my abilities to venture an opinion, but it already looks much more plausible than Flintrock ever managed.