I always start with the idle mixture screws out 1 1/2 turns. Then start her on a high idle and pull a plug cap so she runs on 1 pot and adjust the running cylinder mix screw till I get the highest idle then connect that plug and go to the next one. This must be done when she`s hot which may be difficult if she`s not starting. After your adjustment bring the idle back to normal and adjust your cable slack so the slides pull up similtaniously. As for how tight to go on the manifolds, how tight is tight enough?? Hard to say on a PC but I just go down evenly with both nuts till there is full contact on the gasket and then just tighten about half a turn on each nut. You will feel the the manifold is becoming tight by wiggling it from side to side.
I have in the past in an effort to get out of a tight spot smeared a thin smear of RTV silicon (must be RTV not normal silicone as it reacts with petrol), just tightening down till it made contact and letting it dry over night then nipping down a touch further. I only did this to get me going when the old ones were knackered and I was waiting on new ones but at least you know it`s sealing.
If you need technical information or help with your late dry clutch Ducati S2, MHR 900 or Mille engine - post your FAQs, comments & questions here.