Congratulations! I can't wait to hear how you like them, I've been interested in hearing them myself, let us know.
Nice of jaywillin to loan you the RS1I's, and like ArmAndHammer says, be prepared to spend the money on them, I'm sure you will like them, theres nothing to dislike about them, let us know what you think, enjoy!!!
Buy some 1/8" shaft collars from your local hobby shop, problem fixed. Take a look at my profile photos to see them, there great to keep the adjustment right were you want them.
I'm loaning him a set of Hifiman HE-5LE's to try out as well. We figure this is a good way to save $$$ while trying out different cans. And if we both love what we hear, who knows...?