I have shot at least 5000 shots from vintage bows with 450+ and ultra-cam strings......maybe twice that many! I make my own and have NEVER had any bow show any signs of a problem. But, I pad the loops properly and do not use it on any bow without tip overlays, paper micarta overlays, or with string nocks that are not shaped right(like the old Herters recurves.) I would also not use them on a wood overlay, especially one that is filed very thin under the string loop. On such bows, I use a 12 strand B50 string, on weights all the way up to 65#.
Doug, if I owned your SK, I'd use a 6 strand ultra cam, padded to 14 in the loops....or else an 8 strand 450+, padded to 12. All the naysayers can quake at this if they want....I've seen the results. And, regardless of what they all say: "it's not worth a few feet a second." But, it's much more than that. It makes a mediocre performer shoot much faster, where a good performer will not show all that much better speed. In almost every case, however, it makes a bow quieter, with less vibration. Now, sometimes a recurve is noisier with no silencers, and guys jump on that. But, I've proven to my own satisfaction, that even those bows will quiet down with less silencer mass than a B50 string would require.
Also, if you are one of those especially cautious folks who use 16-18 strands of B50...you're sure to have a quiet setup. But, believe me, you're giving up more than " a few feet per second". I weigh all the strings that come in on the used bows I buy, and then weigh the ones I make for the bow. If you are using 16 strands and any kind of silencer at all, my string will have a mass weight of half of yours. That difference means significant energy transfer to the arrow.
In years of "flying under the radar" and talking with the other guys who were also trying it and laying low.......I've become frustrated. We know it works. But, "conventional wisdom" warns of the danger. I did finally see one bow damaged by a FF string last year. A guy put one without padded loops on an old DH Hi-Speed w/o tip overlays. Yeah, it cut into the limb and ruined the bow. But, if he had put racing fuel into his wife's soccer-mom suv....he'd have ruined that, too.
It's up to everyone to do their own thinking and make up their own mind. PM me for a source of strings if you want, Doug.