What style manifold would you reccomend?
There are a few styles I am considering here
1. Weld nipples to stock elbows, and run one size of flexible hose from plenum to elbows, grind in smooth transition.
2. Grab rail drill and grind, You mention that the 1200 has smaller ports, meaning either I need 1 1/4" bars or ditch this idea.
3. Mikuni Flanges with some manner of mandrel bent pipe, or maybe even steel pipe and weld els?
Next step, sorting manifold.