There are no guide marks on the headlight glass for accurately using standard adhesive headlight beam deflectors for continental driving. Any advice?

Do you have halogen headlights or bi-xenon?

Did the beam deflectors not come with instructions?

 

For halogens:

If you're using eurolites or something similar the current fitting instructions for eurolites suggest digram 2 is correct for a O3 with halogen reflectors http://www.motoring-into-europe.co.uk/download/travel-spot-latest-vehicle-listing.pdf there is also a post in the yeti section about fitting them http://www.briskoda.net/forums/topic/163444-headlight-adapters-on-yeti/?p=2822905

 

Looks like you just need to attach them to the lower left of each headlight just off centre. Might be worth using one with the backing attached at night so you can see the effect it has in different places. Things like this are probably only a best effort and exact placement probably isn't vital

 

For bi-xenons, there should be an option to enable tourist mode and not use beam reflectors.