I am a guy that when I go to hang stands, I actually take an aluminum extension ladder, I have managed to find a easy way to mount a 20 ft er or longer on my atv and still be able to pick my way thru the forest and farms I hunt, I can then carry ALL needed things, from pole saws, stands , steps, cordless tools and so on and the best part of it all for me is I can use the ladder to SEE the view from possible stand locations before wasting time and energy to hang a stand to find out its NOT the best place to be! and needing to move to another tree or??

I tend to do this stuff in off season, many times THIS time of yr when ground is frozen and NO leaves on tree's so I get a idea on view as in most of the later hunting I tend to do!
and also just for ME the ability to hang a stand safer, I strap top of ladder to tree and park atv at base of ladder
I have hung a few hundred stands this way from lock on to ladder stands(having the extension ladder and adding a pulley to tree above things makes pulling up a HEAVY ladder stand simple with ONE person then!, can attach straps safer too IMO

so for me, that is my preferred way to hang stands, I know not everyone can do this for many reasons, but its what I find safest and easiest for hanging stands alone at least!
as gfor harness, I have a few of them, either full on tree service like harness's or the so called one's made by treestand makers/ vest makers marketed for hunters, I have yet to say one is better than another really for what I use them for, , fit to YOU and inspecting often is more important maybe than just a model here , as we all ain;t shaped the same!
make sure its weight rated for you and things you will be holding and carrying while using, NOT just your body weight!