A single VW aftermarket, coil over shock, when used on a 2:1 ratio swing arm...is as limp as a wet noodle. BARELY capable of maintaining level with hack weight alone, when on highest pre-load and over 50% of levelling adjustment cranked in. Add a 30lb battery, and a few tools, and things start going downhill fast.
Been there done that...leverage is a huge deal. Dummy me put a 140/170 progressive on a deal like that and it went to the floor. Jay (Dauntless) happened to have some really stiff shocks (270/320 or something) and I stuck one of them on....almost the same deal. On that rig (yes it was one of my personal rigs) we ended up hooking a torsion bar suspension up and all was well.
Mounting the shock with the top leaning slightly forward behind the sidecar axle works well if you want to fake out a weaker shock and make it think it is stiffer. It makes the shock move more than the actual suspension travel if you get the picture.
Doing the bell crank deal like you are doing can be tricky but is a great system once you have it worked out.