Hardware for 4 arm Kniffen system?

I have some new home grape vines and just put (2) 8’x4” posts in concrete 30 ft apart for a 4 arm Kniffen support system. Hoping someone can advise me on hardware that I can probably find at Lowes:
(1) I read that #9 or #10 high tensile wire would be good. What is high tensile? I saw #9 wire at Lowes but there was no mention of high tensile.

(2) The 2 posts are about 6 feet above ground. I’m thinking of stretching one wire 3 feet above ground and the other 5 ½ feet above ground. Would other wire heights be better?

(3) For hardware going into the post should I use a lag screw and if so what length for my 4 inch diameter post? Or should I use an eye bolt all the way through the post? Or something else?

(4) I’m guessing I’ll use turnbuckles too. What size?



i know this is old thread but thought i would answer. Tensile strength is the amount of force it takes to pull something apart. I am sure for use as trellis wire it is of no concern. you would probably pull your posts out of the ground before you would snap 9 or 10 wire.