Gents, thanks for the tips. Warm (not yet boiling) water in a sauce pan did the trick. I got the ferrules on and tapped them on the floor to get them flush with the tip, dipped them in the water for 5-10 seconds, and pushed on the respective head.
Tomorrow will be epoxy day!
One question: all of my heads weighed within the +- 3 g tolerance with the exception of one. My 54° wedge was 301 g (-4g) while the 58 was 306 g. I have a 5 g weight (thanks to @fatshot). Should I use it on the 54° wedge to make it weigh the same as the 58° wedge? (I do understand that if I use it I will have to first trim the corresponding amount of length from the tip to account for the weight size)
Thanks!