I have two different profiles being swept on an inwards spiraling helix. I've gone through every method I can think of but cannot get a smooth transition between the two features. Currently, I am sweeping both profiles for the entire length of the helix, splitting the bodies at the joining point, then using a subtractive combine to get the cut I want in the primary geometry. This still creates a joint that SolidWorks doesn't really like - fillets hit a hard stop at the point, small faces are sometimes created, etc.
Asa,.. not exactly sure what you're asking but I can see that the sweeps will have some issues because sketch97 with the full R will not match the R0.8mm radius later... and, I don't see that as a problem if I guess how this will be machined?... that is, there will be a change in the tooling at the transition to the top slot... so, it's minor.. and not going to be perfect anyway.. (attached how I'd change this.. but maybe wrong in what your wanting?)..