90 degree horizontal mounting of a camera rig - what's the best way to do it?

[Sandeepthefifth]

Hey y'all. I've been racking my brain over this and can't figure it out... I have a Manfrotto 535K legs/504HD head combo for my 4.9kg (11lb) BMPCC rig. One crucial thing I need though, is to be able to horizontally mount the entire rig at 90 degrees (flip the camera onto its side) while maintaining full pan/tilt capability for a film I'm shooting.

One way to cheat it is to rotate the baseplate 90 degrees and then and vertically tilt 90 degrees, but then I don't have proper pan/tilt control. Also, the rig would be off the tripod's centre of gravity and only held there by a single 3/8" thread.

What's the best way to do this without the whole thing hanging off a single thread, and having full pan/tilt control as normal?

Any help would be massively appreciated - thanks!