Has anyone tried "canned air", e.g. "Dust Off" as a substitute for products like bloxygen? It's a fairly non-reactive fluorocarbon and so should also protect. It's quite a bit cheaper than Bloxygen and I always have plenty around.
I've only used Bloxygen -- and it is great stuff -- but why don't you just try some of your "Dust Off" with a small amount of finish in a small can to see if it works... My mother always told me that "the proof was in the pudding"!
I use the canned air from Sam's club (3M Dust Remover) and it works well for me. I have used it on Minwax poly with 1/2 full in a gallon can and it had not skinned over after 6 months in my garage. I also use it when mixing up batches of "wiping varnish" during a project and it keeps it well.