[EricH]

I would consider such fixtures to be similar to blueprints. In the past, blueprints have been considered to be part of the design--but if you happen to post them publicly, they're fair game to be used.

So if you were to put your design out, and then note that "oh, by the way, we found the following fixtures very helpful to have, here's the design and approximate fit points", I don't think anybody at all would have a problem.

If a rule has a blue box, that can very often be very helpful in understanding what the intent/violations of the rules are.