ok guys, I have tried everything also, and here was my final answer. I also where glasses, (blind in one eye, cant see out of the other. lol) and I have tried everything, although I will day I have NOT tried the MX helmet, but I HAVE tried the Ski Doo modular, which I loved, but I have such a fat head that when I pulled the chin bar down it smashed the breath mask into my face making it ineffective.
My final fix was, and old school open face helmet, with a clear shield and a NO-FOG mask that they "guarentee" will keep you from fogging. Well not completely true, but with a slight modification it will. The no Fog is great, but what makes it even better is add and inch or so of material to the bottom of the snorkel piece on the front, and I added the very thin foam from and old pair of goggles to the nose bridge that seals it to your face around the nose and under my glasses, I have been happy as a clam ever since.
The added inch to the snorkel piece gets the snorkel down below the shield to you're not getting any breath up inside it. I had it longer than an inch, but found out while sitting on my sled, the open area at the botom would somewhat seal off on my jacket and I would fog up.
The NO fog with the added extension will work well for you MX helmet guys too, my son uses a no fog on a MX helmet and does just fine.
You can get no fog from most of the mail order places like dennis kirk, but I have seen them in sled dealer show rooms too for about $35.
98 Polaris XC600 (M10 suspension, Boyesen reeds, SLP clutch kit, SLP can)
95 Jag 440 (daughters sled)
"Speed is expensive, How fast do you want to go?"
"You must be fast, cause when I passed you I was Haulin @$$!"