My thoughts: You've done well with this tree and I haven't posted any junipers that I've styled to the forum that are nicer than this so why in the world do you want my opinion. (Well, there's one, but it didn't get much notice.) If you still want my opinion, I'd clean this tree a little better. Remove all the foliage that's growing downward, clean out crotch growth and growth w/in ½ -3/4" of a crotch. In particular, plucking the downward growing foliage will really clean up the lines of the tree. I'd leave the runners in place throughout the tree until it has backbudding (every)where you want it. It would probably be ok to reduce the top more than the bottom, but after you clean it out, there shouldn't be a lot of shading happening so that will help. If the relative vigor, not just backbudding, isn't completely out of whack though, I'd leave runners everywhere and just be patient for the backbudding to happen where it isn't YET.