Chad,

I think we are talking apples and oranges here. The hi tensile I've seen has been tensioned extremely tight. It will lift posts right out of the ground in a dip on our highly rolling unglaciated ground.  And while barb is often stretched very tight also, I have some that goes up and down hills and is not tensioned as tight as the hi tensile.

I also have had very good luck with 14 gage on usually 5" standoffs on the inside of most of my fences.  I used the Premier 9" on the inside of a very old 4 strand fence rather than replace the fence. It is obviously not pulled real tight but with gripples can get it just tight enough. And being 9" inside the fence it is less likely to get into the old barb than the 5".

On the OP's S curves with hedge I would not think you want to tighten high tensile as tight as I have seen it usually done.  But I am certainly not a fence expert, just sharing what has worked for me. Hope planting goes well for you this spring.

Jim at Dawn