When dealing with these issues, I've been able to make pretty much anything work using one or more these principles:
1) Create a mirror image of an oddball switch geometry using regular track sections on the mirrored side of the curve.
2) If a needed short length of track is not possible, add just enough of a small section to the opposite side of the layout to leave a combination of lengths that is possible on the first side
3) Play around (in SCARM) with different combinations of curve diameters and degrees of turns to shorten or extend the effective length of the curve.
4) If all else fails, an 1/8" (sometimes greater, depending on how many pieces are shifted) gap or overrun can be fudged by nudging the pieces around.
