I too have very wide feet
On the old machine with the slidey bars when I was a kid, the little target thingy never got anywhere near G (widest) it was somewhere about where J or K would have been I think. Coupled with a high instep it makes getting a good fit tricky to say the least. One thing worth looking at is the lacing, got a much better fit since discovering there are different lacing patterns you can use for high insteps (and other foot isues).
I've got my last few pairs from "Shoe Tailor" (jdwiliams.co.uk) as they do extra wide fittings, and they also do larger women's sizes for the wife (who is a size 9, the shops nearly all stop at 8).