Sorry to hear about your problem, but thanks for sharing. I have pretty much the same spec on my PO. I do my own mods, however I've been holding off on the crown and tube as the rep one hasn't been giving me any problems. I did replace the HE valve with a gen, as that is a big tell on the v.5 PO.
One tip that can help to fit the retaining ring, is to put the mid-case with fitted crystal in the freezer, and the retaining ring in the oven, on a low heat, for a few minutes. This will contract the crystal and mid-case, and expand the retaining ring enough to ease fitment.