Advice on setting crown race

[Clancy]

Need advice on setting a crown race - carbon fork and steerer, 1 1/8, Chris King crown race and I'm using the Park tool. The crown race is apx. 1 mm from bottoming out and I cannot drive it down any further. I've used Tri-Flow to hopefully help, no luck. I've whacked the tool until my arm gives out, no luck. I also tried using a heat gun hoping the crown race would expand enough, no luck. However, I was reluctant to hold the heat gun on the area too long for fear of damaging the carbon.

I've seated scores of crown races, never have had one like this.

A lot of the energy from the mallet is taken up by my holding the fork. I realized I cannot rest the end of the fork on the dropouts on the floor for fear of damaging the dropouts.

I'm thinking of using a 3/4" or larger pipe, padded, to rest the fork crown on to solidly support the fork while I wack the tool. In other words, the fork would straddle the pipe which would be horizontal. But obviously this also might damaged the fork.

Advice? Suggestions?