As far as I understand, the ridges on gas regulators are there to create a tight fit and seal it. The jublilees are there to stop them coming off easily. Personally I would get the right hose for the regulator. There is no room for a "that'll do" mentality when it comes to gas!
I agree completely which was why I was so concerned. The 8mm nozzle IGT regualtors do however say that they can be used with 10mm hose so that is what we'll go with.
Amazing family weekend with old steam engines, classic car displays, market stalls, and full catering and bar. And camping on site - Save £25 by booking in advance.