I'll try to make some time to get the configs off my cabs and let you know
Also, stop using the GUI/frontend! Get the games running first, and come back to the frontend if you want to later.
EDIT: configs attached. I use a front end that launches an AHK exe that opens the batfile. Set one cab to master and one to slave, as you have already. I believe a) is the master and b) the slave in those configs, and i also don't think it will matter, but try both ways if you're having trouble. If you're using boomslang's amazing FFb plugin you want the "-outputs=win" setting in the batfiles, the alternative being native FFB, which i believe is actually superior for Supermodel. I have to use the FFB plugin as i want the blinky lights to output as well.
For more info, cab a) is IP 192.168.1.101, b) is 100. Each supermodel.ini points to the
other cab, of course. The supermodel.ini configs also turn off networking and the simulated network board, but the batfiles override that with "-net" and then "-simulate-netboard". You don't have to do things that way, i just did for some reason.