I've had no problem running sockless in Saucony Mirage 4 and Peregrine 2. I just got a pair of the mighty Saucony Kinvara 5 and sockless I get blisters on the outside of my little toes and on my instep behind the ball of my foot. It only takes a few miles to happen, and I'm using baby powder like I always do. Besides this I really like the shoes, I'd like to continue racing in them if I can.

Is it just a hard-to-predict mismatch between me and this shoe?
Are there common mistakes I might have made that contribute to it that I might fix?
Perhaps Kinvara 4 or 6 is better sockless?

Thanks
Alex