So you know know it works with the Z-blob on corners - You can try to calibrate some negative retaction, coasting, wipe, etc, but it will always be a bit bigger than the outline -
Would this be possible?
How about a parameter where you can compensate for the blob size? Like if the blob is 0,3mm larger than outline, then start 0,3mm towards infill instead, and then quickly turn out to the perimiter?