actually saddles are not hard to size if people are told how to fit them and the measurements are given. What is important is to keep in mind where the FIXED loops are. You want them to extend past you hips not at your hips. Same with lineman's belt - if you don't then the hardware, sewing, double layers, knots, etc will contact the hip area and cause pain.
As far as comfort, if you want to sit all day and use a high hook up go ahead - but I have never found lasting comfort with that set upand it PROMOTES hip pinch as the weight forces the saddle to squeeze at your hips (and it doesn't matter where the loops are) only wayt to get around that is to use a spreader or board to move the pressure point out past the hips.
A lower hook up, and pushing away from the tree (i.e. leaners) it takes some of the weight off the hips and reduces pressure. This is basic physical science.
And as far as leaners giving up mobility on a tree (recent video I watched on youtube) take everything with a grain of salt. If I was to use a ring of steps (which I choose not to) and with how I hook up to tree, I can walk circles around my tree for as many reps as I want (because my tether is at chin level and I can easily move it around the tree as I go. The point missed in that video is that the reason why many of us moved to using platforms is so we DON'T HAVE TO WALK AROUND the tree - i.e. we choose to limit the motion ON PURPOSE. But I guarantee you there is not a shot a "ring walker" can take I can also take with my set up.... and I say with far less movement. I don't have comfort issues with a saddle - I sure used to sitting and with a high tether connection. And from reading most of the hunts stories, you will find most sitters very seldom stay for an entire day hunt - I usually stay the entire day which for me is in stand before 6:00 AM and out after 7:00PM in Nov - Oct it is even a longer day.
The other day I forgot my rubber boots so I had to hunt from my saddle with common loafers with no firm foot sole. I hunted for over 13 hours and never had any foot pain.