If you are really serious about prolonging the life of your fly line you should stop messing around and
use self adhesive moleskin on the ends of all 8 fingers as well as your thumbs. Keep in mind that the installation of moleskin is optional on the thumb that is on the rod handle as there is no line contact with this thumb. However, to be completely safe why not just make the added expense of a little more moleskin and do it up right.
If you are really seriuos about this you will remove all of your fingernails. Also during summer months when wading wet you should remove toenails as loose line around feet will cause premature line coating wear. Furthermore, the wax used for ferrules on rods is very effective at protecting your line when used on knuckles, knees, elbows, etc.
You should also consider removing all exposed body hair as the short and curlies really beat the tar out of lines, especially floating lines.
Another item to consider is if fingernails lead to this kind of fly line wear we should really think about some sort of felt sleeve or something similar for guides, line guards on reels, etc.
Just a few thoughts for those extreme anglers out there who want to get the most out of their gear.