I have horseguard and t posts, bought the insulators for the t posts from stateline tack. I called and they added free shipping onto their 30%off! The caps I bought from Kencove I believe, I shopped around for the best deals.
Horseguards website is horrible, I called them and spoke to Gordon I think was the name. I emailed him a google map of my proposed fence layout and he helped me figure out how many tensioners I would need. Definetly get the HG tensioners, and do not let them send you the keepers only if you do decide on HG, ask specifically for the button ones. The newer ones that are just clips do not keep the tension, the button ones do. I have the caps with the tape insulators and the buttons keep enough tension that I have no sagging with only the tpost caps used all the way around my top fence line.
I am broke so I used T posts for my corners and they are holding up great so far. For any gates besides my main entry one, I use the HG handles, for the two pieces of leftover HG I use to keep the pony out of the barn, I bought the cheap polytape handles from Kencove, one of the hooks keeps coming loose and I have to retighten it over and over. If you can swing it, get the HG handles.
2in Other brand polytape is still not as heavy and wind resistant in my opinion. We have gotten decent winds thru East TN here recently, and my HG doesnt move. I really recommend it. I found a woman in Ohio selling about 3000ft of it, all random lengths, about 100 step in posts, and misc connectors and tape plate holders,I am not sure of the technical name, AND a 50mi Zareba charger with a small ground rod, for 500 bucks on fb.
Anyways, saying that to say even though I have a ton of connection points due to the various lengths, my fence is HOT and hits hard when you touch it. We did install 2 additional 6ft grounding rods though. It was worth the 4hr trip there n back!!!
ETA: I have the extenders off my carport legs on a part of the fence, and a tensioner on them and they hold up the fence great too.