DAMN sometimes I am dense---genset hookup

This IS legal. The interlock prevents the main and genset breaker from being simultaneously engaged.
"legal"
So is pissing in public as long as no one sees you.
The point I was trying to make is that the only equipment that should be in your electrical distribution system should be UL and or EU tested and approved for use, that it meet all NEMA, National, State, and Local codes, any thing elses is second rate and subject to saftey and reliablity issues.
When it comes to electrical applications I play by the rules and I suggest everyone else do the same.
Good luck