I will tell you the straight up cold hard truth. You will best learn by doing, the most knowledgeable saddle hunters here can give you the best advice they have but in the end you will only really learn by climbing and practicing over and over out of how ever many trees you need to become proficient. There is no other way. Practicing dozens of simulated climb and hunts months in advance will expose and make known to you endless numbers of problems and failings that at the very least can and will ruin your chances at a big mature buck and worst put your safety and personal well being in danger.
Trying to set up in the dark 60 yards from a bedding area you know a 150 class buck frequents unless you are well practiced and adept at setting up as quickly and as quietly as you can to hunt using a saddle (or for that matter ANY elevated hunting method) is a surefire way to set yourself up for great failure and greater frustration. I speak from experience on this.
I am a complete saddle novice but will use my experiences of trying out different types of hand ons (strap and chain attachment systems VS my pin-ons) and a climber and what I learned from them all VS my pin-on treestands to give you some advice.
First spend how ever much time it takes at just barely (safely) above ground level testing out all you saddle equipment to insure it is 100% reliable and will not snuffer a catastrophic failure and you feel 100% confident you are absolutely familiar with using it before you attempt to go above ground height.
Take a friend (a couple would be even better) and go to a large public ground wooded hunting area with LOTS and LOTS of different types of trees and start picking out trees to climb by imagining they are in good proximity to the type of deer sign you would normally set up on to hunt. Then set up only going up 8-10 feet so incase you have a problem or have to be rescued 10 feet is a whole lot easier than 20' Also to pick less than perfect trees to try to learn what would be trees you should try to avoid and trees you simply must avoid. Then while set up figure out if the tree for any particular reason will not allow you to make any shots and why and adjust your set up and assent accordingly. Also when you just get started learning to use your saddle and climbing above ground level, I would avoid using the same easy to climb tree or trees more than once and make it a point to use a different tree each time.
I don't see learning how to use a saddle is all that much different than a hang on in that you have to learn from some mistakes how not to make them again and it's best to do this when its months before deer season and you're not trying to set up under 100 yards from a killer bedding area is the time to make those mistakes.
As far as shooting a compound bow out of a saddle again you will have to practice yourself and learn. Once again you will learn MUCH faster if you bring a friend along who will position a target or targets at every possible location in relation to you while sitting/leaning/standing in your saddle.
I honestly don't think it will be possible for you to practice to much or try to many different shooting scenarios, especially if you can not do so in a tree where you live, you might find you will need to actually need to drop the draw weight of your bow VS if you were shooting from a traditional hang on stand. Also if you often as I do hunt in cold temps you MUST practice shooting while wearing heavy clothing and boots while in your saddle as drawing a bow and moving about while wearing multiple layers of clothing and a heavy jacket will affect your shooting form and the only way you will know how much if at all heavy boots will affect how you maneuver around a tree is by doing so while you wear them.
I am an absolute believer that you hunt like you practice and prepare and I prepare, practice and set up and hunt out of my treestands like I'm under 100 yards from the biggest buck of my life and one day I will be.