Some are better at it than I am, but I was never able to get side-by-side balanced well enough for me. I found a longer dove tail with the guide scope mounted under worked really well. It's a much cheaper config too. You just need a long bar...long enough to make sure the guide camera doesn'tclip the mount.
Mounts: Explore Scientific IEXOS-100 w Celestron CG5 tripod, iOptron CEM 40
Scopes: Explore Scientific FCD-100 ED-102CF, Various Canon lenses, ZWO mini-guidescope, StarField 60mm guide-scope.
Camera: ASI120MM Mini (mono), Altair GPCAM 130
Control PC: Intel NUC
Loc: 44 -79