The SPF rating system is currently variable. There is a push to standardize the testing procedure but it has not been adopted "across the board" yet. If I remember correctly anything over SPF 45 is "off the scale" and not linear such that it is difficult to compare SPF 80 vs. 50 etc... Then there is the issue of UV-A and UV-B....
I don't understand the post about only burning where sunblock was applied. I can't see how what was applied was a sunblock but: if you really want to stop burning and you are sensative to burning (either from wind, UV or both) look to those who live in a UV drenched environment: Inuit/Eskimos and Desert dwellers. Physically covering the skin with a garment is the only thing that works all of the time.
Your body chemistry can also impact how long a lotion works. Perhaps the way your ride is set up and how you sit, UV is focused at your face? Then sunscreens would degrade very rapidly. Add some sweat (lower pH) to that and more reflection from sunglasses and you may only have 20 minutes of protection from SPF 50 that is a year old sitting in your closet. (If it is an organic based sunblock, they don't last forever.) Remember the SPF system is based off of YOUR sensitivity to the sun. If you can stand 20 minutes without getting burned (no sunscreen) SPF 15 would give you 5 hours of protection: meaning you would receive a 20 minute burn after being in the sun for 5 hours, in a perfect world. Some UV always gets through the lotion.
I would support the advice to get a full face hemet or a face mask. Remeber UV can reflect from many surfaces when you are on a motocycle compared to a car. Sometimes getting used to protection is uncomfortable at first, but in my opion it is a long term investment (like wearing ear plugs). Hope you find something that works for you.
