As noted some months ago:
The Oct.10, 2019 V4Beta Wiki, under resources, shows new scripting properties for Face objects, including face.evaluateNormal( uv ).

Also Jan. 22, 2020 V4Beta Wiki, has scripting properties: face.dropPoint( pt ), brep.dropPoint( pt ), and Updated face.planarFrame().

But at the moment I have too many projects :-)

- Brian

Flow hex center points to frogback.

Process one flowed point.
Face.dropPoint(pt) to get uv.
face.evaluateNormal(uv).
Figure out actual point on the frogback surface, using brep.dropPoint( pt )?
copy gem, using its normal or cplane or something, to align with frogpoint and its normal.
Repeat