Thanks for your response!
My cabin is not pressurized, so I could definitely use the on board GPS/barometer for altitude. 2.5m is more than enough accuracy for my application. In fact, I think a standard vertical tolerance for an autopilot is 25 feet. The purpose of that is so it doesn’t jerk the plane around trying to fix on an exact altitude. I think that also plays into the use of the ‘trim tabs’ - Basically I would want them to be in a neutral position when they aren’t engaged (I will be hand flying the take off, climb out to about 1,500’, as well as the landing procedures - so autopilot will not be engaged at this time). They would be sized such that in the neutral position, they would have a very small effect on the handling characteristics of the plane.
My goal of the autopilot (which is different from some others) is to reduce pilot load while in cruise - especially when traversing complicated airspace where controllers are barking orders like mad. I guess, to that end, if I just had lateral guidance and could hold an altitude that would be just fine with me!
When doing a flight plan in ForeFlight, wind speed and direction is reported from an online type source.
What’s really nice about an aviation app (vs a drone mission planner) is to have an “aeronautical sectional chart” as the basemap rather than a google maps photo. Also, they have an airport database that shows airports and other navaids as waypoints, so you can type in the code of an airport or navaid and it will show up on the map. Anyway, there’s lots of reasons to use one of these apps vs a drone mission planner.