Why not use permanent track spacers, the type that change their own track to match the track that is attached to them. Place two such spacers, connect them with the number of tracks you want up to their capacity. Then as you separate the two spacers, the tracks will stretch between them but keep their spacing constant, even in most curves. Eventually you'll want to add more spacers as they become too far apart or if the track geometry requires multiple curves. If you need to relocate a section of track, moving the spacer moves all the attached tracks as a unit.
All have been available on the DLS for almost six years. Search for "Guide 2t 4m" and you'll find it and others in the series.