Yeah I'm the same as improvement, I want to wear something for long periods of time. I used to use that method and I did feel positive effects from it but I think it needs to be replicated over longer periods of time.
That's a good idea with the rod thing, saves designing a completely new piece, just take the previous idea of reverse pull headgear and change it slightly.
With the retainer its got no coverage of the teeth, do you thing it matters I'm pulling with my palate expander?