U R right Lexan® is Just a trade name like Tygon® but beware they are not all the same formulations.
Makrolon® is another trade name for Polycarbonate
http://www.amco.ws/plastics/bayer/makrolon.asp
The important thing is - what grade.
e.g best Tygon tubin for a W/C rig would be R-3603
Fixittt please post when U have your project finished with Pics

Mat