Well, not finding 610 in my local area, and being a self imposed time crunch (vacation) I've decided to run with what I've got. Marine-tex it is.
After cleaning out the old mast, I used a palm sander with 80 grit paper to sand down the comp-tip for a snug fit all the way to it's collar. Or at least as close as you can get. All the pieces were wiped down a couple times with acetone to thoroughly clean before final fitting then masked off to aid in clean-up. I used the entire small package as it simplified mixing. Measuring down the mast the amount of distance the tip would go, I then proceeded to coat the inside with a thin film of epoxy and then the comp-tip as well.
I pushed the comp-tip in all the way and wiped away the small amount of squeeze out. Worked like a charm! The epoxy was a good consistency to use as it didn't get runny and make a mess.
Next up is the drilling of the holes for reattachment of the tang rivets.