I use the 2 ton (30min Devcon) epoxy you can find at most harware stores for <$3. It is the one with the two tubes connected together! I like it because I can cut the two tubes apart with heavy duty scissors. I then have the two components in two separate syringes. You can measure out small equal amounts easily like this. Also, it is readily available. The 30 min does not yellow as quickly as the 5 min. Also, if you store the flies out of the sunlight they will stay clear longer.

Regards,
Keith