Sean, I've made some A-7 tanks. I did not use kevlar, don't know that its really necessary. Kevlar does work just like regular cloth, but can be difficult to cut.
I have Kevlar shears that I use, when working with it.
I made foam plugs, covered them with Ultracote, then waxed and PVA'd them before covering with glass. I bought these rings from
Todd:
http://dreamworksrc.com/catalog/mach...rt-p-1426.html
And also bought the Sullivan stopper kit, this way I can open it up to clean, etc.
Jim