Bit of info, including flow results, in my project thread.
After putting ours on a flow bench it looked like the upper needed a bit more work to be matched to the lower RS manifold (this had been matched correctly to the head already). Thought i would have a look myself and have a go. Ideally i would have liked some engineers blue to do this but inspected the port sizes against the gasket instead. There wasnt much in it (it had been done before) and I found it difficult to align the two halves consistently to "match" them. Well done Renault for putting only one locating pin between the two halves - as there is quite a bit of float between the bolts and bore holes of the upper i decided it was close enough for me. In the end i just refined the finish of the casting of the upper.