The thing I'd be concerned with is the sub-2300rpm power. On many current vehicles, that's where things are in OD at 70mph cruise. Then how easily it would be to get a kickdown into direct for hills and such. AND how the manifold vacuum levels were at these rpms and such. At which degree of "grade" would it be best to downshift into direct to keep the manifold vac up so the fuel system did not go into the enrichment phase of things.
To me, IF the governors and pressure switches are correctly matched/calibrated, then manual over-ride would be minimal. Keeping it locked in OD might result in lower vac levels and then get into the fuel enrichment situation, which is not the best for fuel economy. Not that the engine would not pull OD in those situations, but at what level of intake manifold vacuum?
It's going to take some "on the road" testing and recalibration, I suspect, to get things dialed-in.
As for dyno curves, Comp Cams has a neat program for predicting those.
Enjoy!
CBODY67