Ah, congratulations! I'm jealous, I'd do it, but I don't think I can make it to Montreal just then (had a great time there last summer though!)
I did RZ solo in Chicago, and while it surely wasn't the completely prim and pretty experience I was hoping for
(some getting bugged a little by drunk guy, some pushing for position, and lord even some small bit of feeling like I was being a bit annoying to some for cheering/bopping-about yeesh), it wasn't as bad as regular GA. I never left once set up (my bladder, I hope, is totally empty before I get ready to stand for the duration, and I drink just a little water as needed thru the show, makes for a much better experience and beer gives me headaches these days anyway lol), but I got to know a couple people who left frequently. For beer, for bathrooms. The first bunch of times they left, all before U2 came on, their spots were pretty much honored, even though they were reasonably prime . I tried to make myself a little bigger to 'keep their space' for them, but this was sorta hard and made me shift over and lose space once they were back. Eventually, after a couple such trips, it was very cramped and I think people were getting annoyed that they kept leaving this against-a-rail spot in high traffic, so their space almost disappeared completely and some shifting occured, as it were. They finally left altogether (phew! I can't imagine letting alcohol take priority, but whatever) and more shifting occured, but it was a relatively gentle sort of process compared to what I experienced, say, on the floor during the Vertigo Tour.
So, I guess then my two cents is that if you don't need to be in the first rows at the RZ, or in the part of the RZ closest to the front of the stage for a few rows deeper even than that, then it's quite roomy a lot of the time and you'll likely be fine leaving for beer and such. If you want to be up front in the RZ then it'll depend on the idiosyncrasies of the crowd I think and while it will likely be much better than regular GA, you can't assume you'll be able to get back to your exact spot anymore because there are surely people trading
up, just much more like party-mingling in feel though!
That was the huge appeal of RZ for me, and it mostly worked out...so much less crowded and stress-over-territory-vibed ! Of course, even so, I'm never so aware not only of how short I am but also of how very many 6'4" men there are in the world as when they seem to appear constantly between me and the stage!