No I just have to buy or build a different USB to R485 adapter, the one I have has a MAX485 full load chip in it and is only rated for 32 nodes as expected. I might be able to just swap chops, I didn't notice anything int he data sheet that would require other circuit changes to make the 1/4 load version work.
CD is definitely the way to go with solenoids - I haven't used solenoid machines in years. 10 years ago it was all Tortoise motors, now I use RC servos, the 9G type. But way back when, a CD power supply is the first electronic project I ever built from a schematic (as opposed to the experiments in my Radio Shack 100 in 1 and 150 in one, or specific electronic kits). At the time I was in N scale (before and now, HO) for space reasons, and I was burning up switch motors like crazy, the control buttons would often stick on and instantly vaporize a coil. So I saw this circuit in a book and built it, and after that, never had a problem. I still have it, but it is nothing to look at, I didn't even use a plain perf board. Just put the 2N3055 in a heat sink (almost certainly unnecessary is retrospect) and then soldered the other components to it. The input and output wires were also just soldered directly to the appropriate component leads. Ugly, but it worked. It's effectively the same circuit but with a 2N3055 instead of the Darlington for fast recovery, also mine has a single 2200uF cap instead of a pair of 1000's. And no indicator LED on mine. I built it in '77 or '78, when I was 11 or 12. Rapid progress in electronics after that - a few years later I built a single board computer kit as my first computer.
I need to play around a bit with the RS485 library for Arduino, as it is, since it connect to the RX and TX pins, the RS485 chip interferes with using the USB port. OK for bench testing, just pop off a couple of jumpers on the breadboard, but to use a Megas should be no problem since they have the extra RX/TX. A lot of my nodes will need no more than a Nano though - but my plan is to just socket it, so if I need to reprogram after deployment I can just pop the Nano off the board. Or just use a pair of pin header jumpers, take them off to program, put them on to run. Depends on my mood when I get that far