Thanks Jordon and aalf. Information is golden!
I'd not seen the leveling bases. Have looked at some bowl type units but then you'd not have an adjustable center column.
I bought some hardware to (try to) replicate a HOG Saddle but so far it's sitting there awaiting further inspiration...
If the HOG is too cheap, there's the RRS.VYCE.
https://soar.reallyrightstuff.com/VYCE-Equipment-Support-MountNote: Triclawps Jordon mentioned is US made.