I will second familiarity of your set up is one of the biggest factors. You will never be able to accommodate for trees, branches, winds. Every set up is a little different. You need to be thinking and moving on your feet. Don't worry about height, don't worry about things from your couch. When you get to your tree and start to climb then worry about your set up. I killed a bunch of deer last year 10 feet up. I could have climbed 20, but I was above the canopy. Your platform is what fits your feet. I hunt a mission, I can spin and shoot a deer directly behind me at 20 yards, did it. I think a ROS would have gotten me busted because I would have left the back cover of the tree and been backlit. And the perfect tree may not be the perfect tree when you get to height, (backlit, branch from another tree, lean in the tree you didn't notice from the ground, get to height and notice a deer trail closer to another tree.....)
All that being said, the biggest obstacle is being dead set in hunting the way you decided to hunt yesterday and not what the woods are giving you today. Never be afraid to change.