Symmons Temptrol Handle Removal ??

I have removed the end cap and the center screw on my temptrol tub/shower valve but I cannot remove the handle. I've tried the puller assembly, banging gently and not so gently with a hammer, and even tried rocking the handle with two screwdrivers underneath the fluted features.

I guess penetrating oil would be next on my list, but I thought I'd ask if anyone has a tried and true trick for this problem.

Thanks for any suggestions.

Problem solved....

Squirt plenty of GooBeGone (Citrus based rubber cement remover) in there....wait 10 mins....then squirt WD40 in ....wait 5 mins...and THEN use the Temptrol Puller. It was still a bit tough going, but it let loose right away...after being on for 19 years!