RE: hayes hinges
When true CA hinges arrived on the market it blew those poly or so called flexable plastic's right out of the water they are so much better. Polys had and still has the worst failure rate of all types of hinge and CA hinge are far easier to use.
Very few suppliers still make polys and their is a really big reason for that. Thank heavens most Arf's now come with some sort of CA hinge and even they have abandoned the polys.
As for Hayes - Yup the very best fuel tank systems avaliable and the only type I use on my new airplanes but the hinges, no thank you.
John