That's the big problem - very sensitive area, and no metal to play with, especially if the port is enlarged symmetrically (same amount at all points of the ID).
I'd like to see some results on a bench from only raising the roof, widening the intake but leaving the floor alone. This lets you do whatever is possible to the SSR, and also moves the active flow higher.
I have a gut feeling that the final throat enlargement might be better if done by hand for the last 1/2" in the arc tangential to the port and blend the throat into the SSR as much as possible.
