Are you referring to the 71" Zero made by CMPro (sold by GSP)?

If so, I use Robart 510W1 with the stock 3/16 wire. They have held up quite well and are reasonably priced. I do need to bend the wire back into shape from time to time since they rake forward a bit, but only after 10-15 landings or so.

Note that 90 degrees work well since the dihedral is accounted for in the mounting rails.

Speaking of mounting rails, replace them before you do ANYTHING. Both sets on mine split horizontally after a few landings -- the wood they use is certainly substandard for this application. I used 3/8 x 1/2" basswood and lots of epoxy for my replacements and they have held up very well. PM me if you'd like details.