Unless your SBK is collectible in some way as is (if so, you shouldn't mess with it anyway), I would just find a competent gunsmith to cut and recrown your barrel to your desired length. I've done it to several over the years, especially before the shorter barrel lengths became available. I think 5 or 5.5" makes a nicely balanced Super, and I have one so configured. My son seems to have laid claim to it, however.