Chris, the 50 does use a recessed holder.
The 80 will do for now, as the enlarger is capable of quite large enlargements, you will be able to do reasonably large stuff with 35mm film.
I often do small prints from 35mm with my 100 enlarging lens, coupled with the very long bellows I can actually make very fine small prints, almost to same size in fact.
The trade off is longer exposures, I don't really think much else would matter.
I would though, look around for a correct 50mm holder, picking one up at the right price, (whatever that may be) when you see one.
Always best not to rush these things.
Mick.