Most likely the stab is designed to be at 0 degrees, and that will become your reference. I believe you said you're flying a BJ Craft plane - other BJ Craft owners can comment on that but I don't recall reading much on people changing their stab angles in those planes.

My suggestion then is to level the plane such that the stab is set to zero and call that the datum. If you don't have incidence gages, set the plane so the LE and TE of the stab are equidistant from a *flat building surface.

As mentioned above, +0.5 at the wing and -0.5 to -1.0 at the motor are very common setups. This is exactly how I set my plane up and it's flying beautifully - I left the stab alone and called that the datum. I added wing incidence to +0.5 and removed negative motor thrust to either -0.5 or -1.0 (can't remember right now). Then I followed the trim charts to get my CG dialed in and to verify the proper settings of the thrust line and wing incidence.

Often it is more difficult to adjust the stab than it is to adjust the wings. Your plane may be different (like if your wings are recessed into the fuse and there's no wiggle room) in which case you may want to set the wings to +0.5 degrees and adjust your stab.

Wing adjusters are easy enough to install. You can do one adjuster at the front of the wing to allow the back to move freely, then temporarily pin or clamp it in place. The typical wing adjusters make it tough to adjust both the front and the back the same amount, but there is a new set on the market which I haven't used yet. When you find the right adjustment you can then make it permanent.