There's a thread about this here: Convertible Top Installation
I made the springs (actually, elastics) using bungees and ring terminals from Home Depot. This was three years ago and they've worked great and held up fine. I made tension cords using
parts from Home Depot. The bungee
part is a tarp stay cut to about 13-1/2" (cutting one stay in half yields enough bungee for both sides). The ends are 12-10AWG ring terminals meant for attaching wires to posts. I pulled off the insulation, used needlenose pliers to spread it enough to get the bungee in, closed it back down with the pliers, then crimped it using a crimp tool meant for electrical terminals. The results seem good but I guess I won't know until it's all together. The bungee in the tarp stays is 3/16" which is a little smaller than the 1/4" you used but it looks okay and fits the ring terminals well. I'm not sure if the tension is right; if not it's pretty easy to re-do them.
The Body Engineering Trim Manual has a good view of how the top of the curtain attaches to the bow on page T6-4745, sectional view CC. It loops around a rod (also missing on mine, yet another trip to Home Depot) then folds back on itself. The rod is then clamped in place by the retainer.
Thanks for the dimensions on the tensioning cords. I made mine way too short (13") but fortunately it's trivial to make more and the bag came with six tarp bungees.
My tack rails are not in great shape but I wasn't able to find replacements. I cleared off the
rust as best I could with a
wire wheel then sprayed them with Rustoleum
Rust Reformer to try to stop the decay. We'll find out shortly if they hold up. The ones on the package tray are the most challenging since they have a complex set of curves to them and aren't just wrapped around straight like on most cars.
