Dang... I need to quit reading the instructions. On the bottom of page 7 of the manual I'm reading it says heat the wear ring until the liner starts to melt. I just didn't expect the liner to be that friggin big. I wasn't sure if you were supposed to reuse them or not either. This whole jet rebuild deal is making me
Wish me luck on my homemade press(shaft in freezer all night, bearing and slinger in oven) this mornings portion of fun. 
FWIW, I have been using a 1750 watt paint stripping heat gun on jetpumps for years. I heat the pump housing with a heat gun until it reaches about 230*F (use an infrared thermometer) and simply knock the wear ring out with a modified brass drift punch. Also use the heat gun to heat the bearing to about 350*, it heats uniformly in under a minute and you don't have to freeze the shaft...I like your method though, should work killer.

I also have a flat aluminum plate the size of the wear ring and a 3/4" threaded rod to use as a press for the wear ring, the rod goes all the way through the suction piece with a flat piece of stock on the seal end...Another cheat is to put the filler strip in a bowl of water in the microwave until the water boils, softens it up and makes things go easier...
I have done an impeller, wear ring, new bearings and seals in under an hour...Hungover on a Sunday morning by the way.

GT