The Magnum 3012 hybrid comes with a 50 amp "pass through" relay. i.e. a "transfer switch". If my memory serves me it is intended for a 50 amp pass through. I may be wrong about that because the install was several years ago, and I do not have a 50 amp RV.
I'm still careful to try to NOT switch while under load.
The correct way to wire a hybrid inverter is to pass all the power through the inverter.
I use a "patch board" so if my inverter should fail, I can wire around it in the time it take to move two male plugs from one socket to another.