Skip: some years back, surveyor's tripods all switched from screw mounts to 3-point quick release mounts.
Overnight, it seemed, there were thousands of tripods, old and new that suddenly became obsolete.
Knowing a master machinist, I had custom camera heads made for a nice price and the $300 - $400 'pods were free.
My favorite is a beat up stained cherry color (mahogany). I rack a Nikon Prostaff 82mm spotter on that, steady as a rock.
Find a survey office,see what they have, gathering dust. There were several "weights" of 'pods. One might work for you.