I've been thinking about this for years. This thread gave me the will to tighten by hand, and the fallback of buying new strings from Sumiko if something went wrong. It's tedious, but with some good music...
Not sure if the string grilles work quite the same on other SF, but with Stradivarius, I simply inverted them so the "bottom" of the string grill was facing up. Then, one by one, put a new knot in the string about 6-8" in. Cut off the excess. Inverted the grill so bottom is facing down. Big visual improvement.