Longer arm / dual mount arm?

[DiscoStuart]

Looking at getting a Cade 600 S2 - 600m Cube, but with the overflow at the back, itmeans the distance from the mount to tank center is 400mm.

For the K7 Pro v3 - what is the arm length? And is there a longer version available if it can't get to tank center?

And then separately, what would you suggest for someone trying to mount two? Any custom double mount arms or other ideas?

Thanks!