Honestly, finding a string for jazz pizz that slaps well is easy! Finding one that does this and bows well is the challenge!
Here are a few that I have used that I thought were great at slapping and pizz:
Eurosonics- the light set- nice and growly pizz with a good amount of sustain and great for slap- full disclosure: I never used the low E, but the rest of the set ROCKS imho! The ultra light set gets love too.
Weich gauge or use the strings called "solo" which are designed to be played tuned higher- if you tune them to regular pitch they are crazy light and nice for slap...
Velvet Blue- also good- I've played them a bunch but never on one of my basses.
Then there are all the Innovation brand strings- I haven't used any but they get high marks here on the forum.
I also hear that Pirastro Evah Pirazzi in the weich gauge work great- I've yet to try these too...
Of course, then there's gut...
I'm a big fan of Gamut strings- I use the Pistoy variety as I really need a bowable string myself...I had to go through most of the above listed strings before I got to Gamuts, as well as lots of other guts.
If you have no intention of playing arco try one of the above listed strings, or just get a set of Lezners if you decide to go gut! Great and inexpensive (for guts that is
Good luck in your search!
PS: Thanks for your service!