Alignment for curve

[[To...]]

I should know this but my brain is a bit foggy.  I have a face groove detail on a cylindrical part.  View shown below is from the -Y direction.  The Z depth of this groove has been problematic for reasons I don't know.  The drawing is calling for profile of 2 radii within the curve.  If I take a point in the -Z direction at the bottom, where the 2 radii are tangent, I believe that will give the curve enough information to locate it for measuring. Will a geometry best fit alignment from the point do the job? 

 

Edited 22 hours ago

[[Ri...]]

Sure? You could also just create a new Alignment and fill in that point as the Z Origin - it should net the same exact result, but with less steps.