Daze, not saying finer cheesecloth is better, frankly my latest pressed Gouda
looks boring compared to yours.
On brining times, this recipe
(currently) says 3-4 hours of saturated brine per lb/0,5 kg but I think that is too general, as it doesn't take surface area/weight ratio into account and thus smaller cheeses should need less time per weight than larger, so I think you should be OK, next time you could brine longer and compare results.
Gouda's can be aged years if want, question you ask is how long can you 100% natural rind before waxing or vacuum bagging? Me, I don't want the hassle of waxing, so I've been 100% natural rinding them, which I'm finding is very tough. Here's a thread on a dark mold
problem I have/had that was very interesting and another on a white deposit
that was better news. Through those two threads Francois really opened my eyes to problems of natural rind aging Gouda's. Also, this thread
was illuminating for me on oiled rinds.
Hope that is some help to how long and perils of 100% natural rinding your cheese.