Quick question: How do you measure incidence if you don't have an incidence meter?
Quick answer: you don't.

It seems like I have to always give a lot of down trim to this plane every time I take it out for the first time of the day. Then as time goes on during the day, I can come back on the trim some.
This may be due to the nylon tube in a tube rods. Real Golden Rods don't have much expansion/contraction. I've measured less than 1/32" total from 200 degrees to 32 degrees. Cheaper nylon rods will contract and expand more, giving the trim problems you describe. Also, the outer rods MUST be well supported, no farther apart than every 3".

It is also somewhat sensitive to wind which most people tell me that low-wing planes are usually not affected much by wind.
Not true. The placement of the wing doesn't affect wind sensitivity. The wing loading/weight and airfoil affect that the most.

Dr.1