ORIGINAL: daven
Don, if you are using a servo hatch, you can glue a piece of string to the hatch and tie the other of the string to the battery charge lead. To check your battery or charge the plane, you can remove the servo hatch which has the correct lead attached.
Also, if your wing is properly potted to the fuse, you should not be getting trim changes after removing the wing.
Dave,
Because I have the field behind my house, I often leave planes together for weeks at a time. So I like to be able to charge them easily. The MPI MAXX switches are convenient for that. For Club 40 where there is no hatch and they aren't that fast, the drag is a non-issue. And on the Quickie 25 planes, it isn't as much of an issue either. I would never use the external switches on a 428 plane.
Where I have had trim change issues is on the Viper. The sides are thin. When you mount the wing, it is easy to change the incidence slightly. Look at the bottom of any Viper wing and you will see indentations from the sides and the wing hold downs. Admittedly, if I took the time to pot the wing, I would not have the trim issues. But now I'm going to be flying other planes, primarily the Smasher and it is a fully molded wing saddle, so trim changes should be a non-issue.