Anti-fog solution for Caberg Justissimo GT?

[G]

I've got a Caberg Justissimo GT and was hoping to get a DIY pinlock system to add to it, as I was really impressed with the one on my RAID II.
Seems that the flip-front helmets have a double-bend in the visor, meaning the standard ones don't fit.

Can't find any signs that pinlock or fogcity do anything for it.
I've tried google, but unfortunately the standard visor is sold as 'anti fog' I believe, so I just get replacements for the standard one.

Any ideas for similar things that work; ie not liquids you spray on and have to redo every use etc .