Help with RAM style mounts

[BO-105 CBS-5]

Hey guys, my first post here. A LITTLE off topic but I know you'll have the answer.....

I need a RAM "style" double ball mount with a long "mount plate" (with holes) to secure a Icom chartplotter and Humminbird sonar side-by-side horizontally at the steering pedestal of my sailboat.

The RAM mount has an option to mount the base "ball" to the vertical portion of the round stainless grab rail above the pedestal, however, their web site is so poor I can't determine if they have a plate with holes long enough to mount the insturments on....or if one is available with the combination of parts to make the thing fit. I would prefer NOT to drill into the flat fiberglass top of the steering pedestal.....not much room....so getting the lower ball onto the grab rail is preferred. I know RAM can do this.

The mount plate must be at least 8" long to at least accomidate SOME of the screws from the OEM brackets of the instruments.....eg: they'll "stick out from" the end of the plate a bit on the ends. No prob. here.

Any suggestions for RAM or any other brand electronic vehicle mounts I can consider?

My thanks in advance.....Joe