Mark, I use U-40 Rod Bond paste epoxy. I comes in 2 versions; the original has a long work time, at least 2 hours. When I'm doing a batch of baits, I like it because I can do the initial fitment, then mess around with the lips to my heart's content until I get them just right. You know how that goes! Rod Bond recently came out with a quick cure version with a work time of around 10 minutes. I've seen several other brands of paste epoxy now being sold on rod building supply sites like mudhole.com but haven't tried them.
I got onto Rod Bond since I occasionally build rods and use it to glue up grips. Decided to try it when I was replacing a broken lip and had to enlarge the slot to get out the broken lip. It worked great! No dribble, no voids, and very strong. Since then, I often use Rod Bond whenever I need epoxy and am in no hurry to get the job done. Mix a batch and you can use it to install all the hardware on a batch of 5-6 baits, without hurrying. The lazy man's epoxy.
If I really bugger cutting out a broken lip and am left with a huge slot, or want to completely fill in a slot and cut one at a new angle, I go with an epoxy putty stick. It mixes to a clay-like consistency and cures hard in 5-10 minutes. Has a density similar to pine or basswood. I've used several brands, all seem similar and are available at any home center.