Thanks a lot for the help, whats the difference between the first and second definition though? Will the second definition give an average for each tangent, would it be the same effect in the first definition if I connect one slider to both Vector factors?
In the first one you can adjust the magnitude of the tangent vectors manualy.
The second one uses the curvature radius (for no good reason whatsoever) as the vector multiplier, so it's fixed for two referenced curves.
No, it wouldn't be the same if you connected one slider - try it and find out :)
Anyway, those are just examples and you can read more about different blend types in the main rhino help file (search for "continuity")
I'm not sure if it's possible to define G2-G4 continuity in GH though.