Thanks for the reply Jef. The Silhouette Bass Guitar strings look like the right gauges and the scale length is similar enough (the Stingray is only 3/8" longer), that it should be a good match.
The Silhouette strings worked great on the SS SR 4H. I tried it with both the 54 and the 74 as the bottom string and the lighter gauge worked a lot better. Less tension and a brighter, clearer sound; especially on chords. The guitar style ball ends are just a little too small, but it's easy to shim them with a small washer. The core on the wound 20 is so small that you can't really bend the string too much before it breaks. Overall, it was a fun experiment.