Thanks for the replies so far.
GrahamS; I’ve read mixed reviews about the Smith goggles, mainly to do with the power and/or number of fans. I think the older ones had 2 fans while the new ones only have one? Also I like the wide angle vision of my Oakley Flight Decks so would rather use those.
jemima: I’ve seen those but my Oakley frames have a 15mm gap where the foam/ventilation is at the top. I’d rather not have the fan sticking above the goggles as it might rub against my helmet.
I’ll post pictures once I’ve got it working along with test results.