Markus,
OK Depending on how you source these it may not be cheaper than just buying a complete rig, but if you have some of the bits it will make a nice mount. You need to add...
1. Tripod - I have one, good enough.
2. A dovetail base - I have one, eg
https://www.aliexpress.com/item/Dove...9-2d91ab8d1c5d
3. 2 x M8 cap screws to bolt above onto the head.
4. Counterweight bar and counterweight. The bar must have a 3/8" thread to fit, and the weight needed is 1-2kg.
Alternatively a trip to a machine shop to have the hole drilled and threaded for M12 - which I may have to do - as I have a spare bar (and weight) with M12 thread. I've already contacted Hercules and suggested they make the hole M10 or M12 n future to match the commercially available bars.
BTW the belt drives give a reduction of 8:1.