Disassembled Headlight
#32
have you though about the windshield tar that is used to reinstall windshields? It has the same consistancy as the rubberry crap that is on the headlight. Try heading to any automotive joint (kragen, Oreilly, autozone etc.) and check it out. There is a flowable type in a tube but they also have a rope style that I think would work great.
#33
What about automotive seam sealer? You can get it at any automotive store and it should be good for high temp. Pretty much along the same line as the windshield sealant. I have a few tubes laying around if you want to try.
#39
If you haven't found a glue already, you can get CA at your local hobby shop. A 1 ounce bottle will be more than enough. About $10. You would want medium or thick formula so it does not run. You must also be carefull or the fumes will smoke the plastic.