Not a bad idea, tippy. In fact, when using a Roto-Pod to learn nose-in, we did a similar deal; make a separate set-up so the main blades never go to positive pitch. This keeps the ship firmly on the ground while still allowing free movement of the Roto-Pod mechanism.

The only problem I see with your idea is ground resonance. That can sneak up on you in a hurry, and will destroy a machine in the blink of an eye.

I have some rough plans, somewhere, drawn for a set of all-aluminum head loaders with an adjustable drag hole set-up to accomodate different blade grip spacing and a removable weight system to adjust for different needs. A good friend is a retired machinist who said he would be glad to make them for me. I just never followed up on the idea, and am not likely to now.

If you guys do find a set of head loaders, be aware that the whiffle balls are the weak link. I had one fail and turn inside/out on me on an X-Cell 60, and the machine was a heartbeat away from destroying itself due to dynamic imbalance when I chopped the throttle. And, as with most nasty things that go wrong with helis, it happened FAST.