Oh, I forgot to add this one thing:

If the servos are pretty close, fly the plane and see if you actually notice it in the air. You may not. You might need to get someone who is a really hot acrobatic pilot (pattern or IMAC, not free-style or 3D though) to test fly it and see if it's worth fixing.

(the reason I say pattern or IMAC but not free-style/3D guys is that in pattern and IMAC, the planes are flown very smoothly and percisely. Any bad tendancies show up on their score cards, so these guys really KNOW how to trim a plane and they are really good at figuring how what is wrong with a plane in the air. Guys who just bore holes in the sky, or spend all their time hanging on the prop don't always have the experience to really fly the acrobatic routines smoothly and percisely. For them a 3D-only guy, a very slight roll coupling with elevator might not be a big deal, but for a guy who flys percision acrobatics, it would be huge.)