I recently replaced the main dovetail on my large refractor with a Losmandy plate which set a large fixed distance between my tube rings, leaving me with a problem as to how to mount a guide scope symmetrically on top. The flexible hole spacing on this bar is an ideal solution and allows me to use either my small guide scope with an Arca Swiss clamp or my larger one with a pair of Vixen clamps on its tube rings. A symmetric arrangement mitigates any need for 3D balancing and a top dovetail allows for fine tuning the DEC balance as well.

With spacing determined elsewhere the extended long hole pattern is invaluable.