It seems I forgot to respond, sorry for that. Fall, early winter and late winter are the best wiring moments for most junipers.
As for the design, I think this could work! But in general people advise against having branches on the inside of curves. In your case, that's the only branch left ;-)
No branches on the inside of curves is a guideline of course, it's your tree and if you're happy with it, then it's alright.