Ground poles are always a good idea when introducing a horse to jumping; even if you introducing a really experienced jumper to a jumping lesson! I personally feel they help to sharpen up the horse physcially and mentally.
As far as re-introducing him to the actual jumping, take things gradually - first run him through the uprights completely on their own, then run him through with a ground pole a few times, then maybe a very small jump that he can more or less hop over and then from there gradually increase the height. Don't however push him so that he feels out of his comfort zone - get him used to the jumping routine within his zone for a few days/weeks (depending on how often you ride etc. etc.) until you feel he is as confident as ever before you start really pushing for higher heights. Don't forget though that a grid of smaller jumps does so much more than one massive jump in terms of training - I would personally challenge him with a course of jumps first before pushing the height boundary. It's not much use having a horse that can jump 6' or something stupid if you can only do one of them - even a puissance horse does two!
It maybe an idea to get a friend to do the pole work for you as getting off can cool your horse down so that you have to warm him up again before he is compliant once more which will take absolutely aaaggesssss with this rountine.