Set your first post (the highest side if there is one) and then set your receiver and staff up to suit that ones height. When you have got the next one set up use you receiver on that post and adjust post accordingly, bringing it to the right height. There is usually 5mm or so tolerance so bare that in mind.
I use 2.5mm wire and do however many termination knots i need to suit the netting, leaving enough of a tail and then crimp the tails to the netting and job done. Tieing off horse netting is very fiddly and also netting is much more likely to snap whilst doing so than straight plain wire. Alternatively do the same using standard gripples and use it to tension to, especially on shorter stretchs.
I think the bottom line over here with our treatment is it doesn't work, regardless of treatment penetration. Timber species is important but since 2004 when the arsenic was removed from the CCA treatment they may as well be spraying them in green paint for the level of protection it offers.
Make your own... I did, cost about £500 all in, specifically for deer fencing although will do all other heights.
Mounting it on the front loader of a tractor is not the best in my experience unless it's very large and we'll built. A tele handler is much better, stronger and you can simply boom out to tighten. In the mud I have had issues with the netting/clamp arm being so far to one side that the tractor gets pulled about when driving forwards to strain up. But less so with a tele handler.