beautiful Hellcat Scigs, as usual

I had a couple questions also:
First I notice on some of your builds you have something yellow wrapped around the thrust bearing, I assume to make a tight fit into the cowl/former. What do you use for that?
Second I notice with your last couple 500 series builds you've stopped building nose blocks and just mounted the thrust bearing directly into the cowl, any particular reason for that? I'm ramping up a run of 500 series and am doing a lot of looking around for different things people have done.
Thanks,
Kevin
not your average nut.