The only person that's commented, after posting on 3 different forums, about replacement strings for a Kestral was on a online retailer's website on 4/4/16:
Ernie Ball 2833 Hybrid Slinky Roundwound Bass Strings, $17.96
"As a direct string gauge replacement for my PRS Kestrel, these strings really brought it to life. They're so much more responsive and articulate compared to the stock strings PRS puts on their basses. Overall, they've improved my tone by leaps and bounds. They sounds nice and balanced for finger-style playing but also provide some nice, deep chunk for picking/more aggressive playing. My only gripe is I didn't put them on sooner."
So that's that, they're from one of the biggest names in the string business, under my price point and they are on order right now.