Bruce,
Interesting observation on the Ross switches. On my old layout I was able to run my large steamers (Lio PRR T1, MTH T1, J, and Q2) through their Regular (about a #5.5) at speed without issue, even a crossover.
Have you had problems with your switches? What size are they? While I've gone to mostly #6s for my crossovers, I'm using some #4s to save space in one area so I hope they will not be a problem.