Back in the good ole wiring days, we used handy boxes as j-boxes to continue the run to ??? other outletd. I have not been able to run this down in the codes yet. Any help on this would be helpful, thanks much.
Also, is there a minium height for sub-panels outside? thanhs again.

I'm not sure exactly what you are asking, but if you are asking if you can splice in a handy box the answer is yes.

In reference to your question about panel mounting height minimums, the answer is that it is not addressed and therefore there is no minimum height.