Canon only plays nice with Canon RT. I called Sekonic and asked if they were planning to build a Canon friendly RT module and they said no. They are in bed with PW. That was 4 months ago and you never know.
When in manual I carry my STE3 and L-358 with me. Flashes in group mode and I use the test button on the STE3 to fire the flashes. I set them all at each location using this method. When done I put the STE3 back on my camera.
I modified the foot stand and attached a spare BR connector.