Hey, you're getting all the same Macs as I've got! 
Anyway, 36 MB in the 520 is nice, you'll be able to run OS 8.1 on that - mine only has 8 MB and so has to live with 7.6.1. The memory upgrades for 5xxs are usually very hard to come by.
That G3 is a bit ugly with that extra CD drive with the non-CD bezel though, are you going to try and get a blank bezel for that (or a second proper CD bezel if you want two CD drives)? Don't forget that you'll need a PCI graphics card for it if you want to install 10.3 or 10.4 though (recommended, unless you're only going to put Classic on it, as 10.2 is rubbish). You shouldn't have the Rev A Rom with lack of slave drive support though, as the 333s were the last Beigeys.
Anyway, 36 MB in the 520 is nice, you'll be able to run OS 8.1 on that - mine only has 8 MB and so has to live with 7.6.1. The memory upgrades for 5xxs are usually very hard to come by.That G3 is a bit ugly with that extra CD drive with the non-CD bezel though, are you going to try and get a blank bezel for that (or a second proper CD bezel if you want two CD drives)? Don't forget that you'll need a PCI graphics card for it if you want to install 10.3 or 10.4 though (recommended, unless you're only going to put Classic on it, as 10.2 is rubbish). You shouldn't have the Rev A Rom with lack of slave drive support though, as the 333s were the last Beigeys.