The 25# bow will be fine for form work, but your hunting arrows will fly funny from it. You might buy 1/2 doz arrows for the 25#'er just for form work.
You can get carbon arrows in a variety of gpi weights. Some like adding weight to the front, some like keeping the weight spread out (tubes). You might consider going to a carbon/aluminum shaft for greater weight (such as Axis FMJ). Check out some posts on Front Of Center (FOC) percentages and see the effects of overloading the front end.
Instinctive shooting is what happens when you have learned what good form is, figure out a sequence for your entire shot from nocking the arrow to post-release, then practice that sequence until you do it automatically. When you do everything right without thinking, you are shooting instinctively. It takes lots of practice.
Shoot seriously at distances you are comfortable with, but always include several rounds at longer distances to get used to them and to make shorter distances seem easier. If you want to shoot comfortably and consistently at 20 yds, include a lot of shooting at 30 in your practices. Shoot at small spots rather than BIG spots.
Most of the people in the world shoot split finger with their index finger at the corner of their mouth. Good way to shoot.
If you are going to shoot from a stand, practice from a stand as much as possible.
Tuning the bow/arrow combination will result in maximum speed for your setup. Most trad shooters shoot off the shelf, but some prefer a raised rest. Just a matter of taste. See if you can find a 12 strand B50 string for your bow -- might add some speed is the string you have has more strands. You can't tune a bow perfectly until your form is consistent, so get as close as you can and keep working on form. Practice, practice, practice!
The right brace height will affect arrow flight, bow performance, hand shock, and noise. Shoot without silencers on the string to find the right brace. Most bows are pretty quiet without silencers when tuned well. Size and weight of silencer will affect speed. Catwhiskers take off a couple feet per second, big fur silencers may take 5 or 6 feet per second.
Invest in a good field point target for your thousands of practice shots, then get one of the inexpensive, heavy, closed cell foam targets for broadheads. If you get everything tuned pretty well, shoot a field point, then a few broadheads to see if they hit the same spot. The foam will last a fairly long time. No target will last very long with broadheads.
Proper form may have a few personal touches. The more you practice, the more your personal style will conform to accepted "proper" form.
Canting the bow is a personal choice at accepted hunting distances (<30). It may be necessary from a stand. If you start shooting longer distances you will probably start holding the bow closer to vertical.