In all honesty, trying to dial in the trim settings for each plane could actually cause more problems than it may solve. You're best bet is going to be simply flying a trim flight for each plane and re-trimming out the plane. Once you have the plane trimmed out you should then work with each plane to mechanically adjust the plane so that they trim on the radio is as close to neutral as possible. If you do this for each plane then moving a plane to another radio in the future will not be an issue since the plane itself will be in trim and not need the radio settings to trim it out.

Ken