Anime, do you sell the GMH? If so what size is the rf topper? I had a member ask me if one of my kits would fit it.
Regarding the helmet question, you really can't go wrong with any of these, be it the fph2, GMH, Asok, anime fans helmets. They all are top notch so you really can't pick a bad one. Just stay away from eBay if you are looking to get a lid, those are junk recasts.
No asok took over the gmh, but he used the same rf toper as from his budget so your light kits will work for any gmh kit made by asok.