It definitely is an old design block, I specifically got it because I didn't like the CSQ circles. But they've grown on me and I don't mind the look any more. The new block I've got is the CSQ design but it's copper I think I'll just stay away from the Nickel it doesn't really matter to me anyway.

My loop is up and running right now and works great. I think I even got the tubing a lot nicer. I think you're right about the plasticiser being the cause of that stickiness on the acrylic. Maybe that is what was causing the pump to be so hard to turn as well if it was sticking to the ceramic ball or other parts inside the pump etc

Hopefully all smooth sailing from here!