[Auhydride]

Here are some thoughts.

Hm, It seems like the fogging is because of the type of glass RX lenses use, polycarbonate doesn't fog, since it doesn't transfer heat well and doesn't store much heat, think of a steel plate and a wood plate, keep them near your mouth when they are at the room tempeture, the steel will cause water in your breathe to condense and wood won't. So no matter what you rub on it, it will fog up, since it takes heat away from the air, causing the water to condense, applying chemicals on the surface can help to reduce the amount of heat transferred maybe, or just making the surface harder to grab onto by water atoms.
So, It should be as warm as your body, maybe warmer, so the water won't condense.
In theory, heating up the lenses work, actually, i heat them up with a small lighter torch before wearing, and don't get fogging at all, but eventually it will cool down below the body tempeture. I can try heating up the glass a few degrees over the body tempeture, but it wouldn't be so comfortable.
Second idea is to drive moist away from the glass, less % of water in the air means cooler lenses required to condense on, since the water in the air will be more stable.
Goggles do this by opening holes on the goggle to allow air to circulate as you walk or by itself because of heat difference, but when it's not enough, you need a fan.
Bolle t-800 wouldn't have space to install a fan though.
Now i will check if it's possible to use an external air pump to provide air through air pipes, with enough fresh air, it's not necessary to heat up the lenses.
I bought a battery powered backup pump that are used in aquariums, they are really small, and use D type batteries, i will install smaller batteries and maybe use two pumps, since the pumps themselves are small, maybe i take them out.
They aren't loud either, i need a small silencer installed on the pipe (a pipe larger than the pipe and maybe have walls inside it) other than that, the pumps just make a low humming sound, which can be muffed by some foaming, and keeping it inside a bag.