Well, he is thin. Just not as thin as you made it sound like. At least not from your pictures.
I would go ahead and offer him food on Saturday, then maybe feed him every 5 days until he plumps a little.

To me your idea of quarantine is a little off. I know you keep resetting the clock, but that is still not going to help if you bring in a sick animal and loose them all. I know how hard it is, but you need to stop adding snakes until the 60 days are up.

Just stop and ask yourself how you'd feel if this new snake WAS carrying something and you lost all of your snakes. Not only did you loose your companions, but all your investment as well.

Really, there isn't an excuse for not doing it right. You may get away with it once, maybe a dozen times, but sooner or later it's gonna bite you in the butt, and then you'll be sorry.

Gale