I have a twin cheetah rafale. Did exactly like you mention, but instead of switches, I just have the connectors to the Y handy.
I start both of them at the same time (always with the data terminals), and if for any reason, one doesn't start (it never happens by the way), I just unplug/plug and start it again, while the other is running (or starting). Simpler than adding more switches

Regarding cross talking, in the rafale they are very close to each other and have never witnessed this problem (they are in separate bypasses though, so that might help).

So far i have about 50 flights with this setup, and the only flame outs I had were fuel system installation related. Once that was sorted out, it has been flawless