Eric,
The hidden rudder bellhorns are not applicable to the VariEze - there is really no room in the VariEze winglet for such an arrangement. As for the Roncz, it was never tested/approved for the VariEze. A few builders (2 that I know of) have used it (cut down in span) on the Vari, but such an installation & testing is not for the average soul.
Overall, I would recommend a series of small/incremental changes to your new airplane over time, rather than a whole bunch of significant or Major Changes in close proximity.
My 2 bits,