You really want to get this as accurate as possible. It is amazing that squeezing an aileron an imperceptible amount can make a difference. Imagine misaligned surfaces!!
Generally, get the flaps rigged first. The bottom skin flush against the fuselage. This is a solid baseline. Next the ailerons. Work and adjust the rod end bearing until you have perfect alignment. It may take a half turn at a time.
I like to clamp the aileron to the flap. This makes adjusting the rod ends easy. Adjust until the bolt will go through the rod end and the bell crank. Make sure the stick stay in the same spot!!! Don't forget to tighten the jam nut!!
Finally time to bring the tips into compliance. The alignment holes will generally be pretty close from my experience. Adjust the flanges of the tip to get the alignment correct.
Now work on the aileron to tip gap. Fun with fiberglass!!
