Tim, this is what I got back from a Rotax expert apparently the tolerances are not available outside the overhaul shop.
Hi Garrett,
There is a part available for the exhaust port repair:

The AR in the table means "As Required".

The k refers to an endnote.

Item 27 is intended for just this purpose, but per the footnote, there is some machining involved. The necessary data for doing that machining is in the Overhaul Manual, so the work must therefore be done by an Rotax overhaul shop. [END]
You could also consult a machine shop to come up with a repair like machining the port then install a sleeve, when faced with replacing the heads you do not have anything to loose. Europa may have a newer exhaust system that is lighter/more balanced weight wise. Also worn out motor mounts may have contributed to the damage of the exhaust ports.