Howdy,I've got Mike Holt's illustrated guide to the National Electrical Code 2017 and it has a great chapter on grounding and bonding. I've read those 95 pages several times now and highly recommend it as a resource. I'm not an electrician (not even an internet electrician) so do your own research and form your own opinions.
The reason for bonding in one place and before any load is to prevent a parallel path for neutral current traveling back to the source. If you bond it in the wrong place, or multiple places, neutral current will flow on the ground conductor, and then everything tied to the ground conductor becomes a shock hazard.
Another scenario where this principle applies is when you run a feeder from your main breaker panel to another panel. In that case you run two hots, neutral, and ground to the panel. You do not tie the neutral and ground together in the panel being fed, that only happens at the main breaker panel.
My thought for load testing is to bond the neutral and ground just like when you generate with the house: in one place and before any load. On the other side of the twist lock I'd tie neutral to the ground rod and leave the bar off in the generator. The generator will be grounded via the cord, just like it is when generating for the house.
When the generator is grounded via the cord, that connection is keeping all the metal parts of the case near the same potential as earth. Adding more grounds helps reduce the impact of lightning on the unit and attached wiring.
-- Carl
What you have done is fine. You have made your 4 wire cords, when connected to the house, you are using the ground in that system. When you hook to your panel with the 4 wire cord, you are fine since you have it set like your house. Neutral and ground bonded in your mini panel, with ground rod attached via a wire to the mini panel.
You have it setup with not needing to make changes with the generator bonding strap.
Good Job.