To reinforce the firewall you can do it from the outside if you want to pin the firewall. You can do it by using small tack nails or you can drill and then glue in small hardwood dowls.
As for the fuel line I use the clear yellow line, if it is tygon I cannot say but never had any problems.
I'll send a picture of my 60 Ultra Stick firewall that I pined with tack nails, works very well. I'll send it in my next reply" I have to take a picture of it first.