You walk into our rat room and what you smell isn't the domestic/norway rats. You smell the ASF! They are VERY smelly compared to rats. We have to clean their tubs twice as often as the rats. Mice smell horrible too. Litter size varies. Sometimes you will get 17 in a litter. Sometimes you might only get 5. Our ASF's average about 12, which is on par with our normal rats. They do grow rather slow.
Racks are the only way to go if you're keeping large numbers of rats, but seeing as you only have a couple snakes, it might not be worthwhile. You'll be overrun with feeders. Tubs are a LOT easier to clean than tanks, though. I can give ya some measurements/parts list on ours if you need. A 4 tub rack takes about an hour or so to build and costs about $50.
Might I ask why feeders are so hard to come by? Where in the world do you live? I've lived in some pretty remote places and there was always somewhere within driving distance that carried mice. Every pet store I've ever been to carried mice.