Well, let me put it this way: do you think that in order to have the aforementioned 95 games, I would have to do some advanced compressing? I guess one could assume they won't all fit in there with literally zero compression, but would simply packing them once possibly suffice - in your opinion? I mean, since you have so much experience in these matters (by looking at the number of videos you've done on the NESCE), I trust your judgement. Let's say you wanted to put those games on the NESCE yourself - would simply looking at the project make you think "Yeah, this is definitely going to need some extra work", or, "These will probably fit just fine after compressing them just once".
I'm not sure if I have the patience / courage to start learning all these advanced methods; I think if that was the case, I would rather just start cutting down the list. And yeah, all of this is just speculation but I guess I just like having my mind at ease...
It isn't too complicated You have to figure, roughly 381.6 Mb if it is similar to the Nand Flash we currently have. Of that, there is memory you really can't touch. So, it comes down to closer to 330 Mb or so, that you can get on the Mini NES. BUT, this is where things might get tricky. the SNES Games, if considered permanent memory on the Mini SNES, can pose a problem. We may have to "delete" them from the Mini SNES to even use that space. 20 Mb or so for the 30 NES Games on Mini NES. It will be MORE for the 21 games on Mini SNES. So, that is just one obstacle. We will likely need a modified version of hakchi2, once and if a hack mode of transportation is in place.
As far as your question. It is simple. Take the games you have, and 7zip them all. Whatever size they end up being...If under 330 Mb (Number to possibly change with the SNES 21 Game issue), may have a good chance at working, if the Mini SNES pans out.