Probably worth mentioning, while they may only be Kevlar core gator line with some special treatments, and they may not be pricey/high-brow enough for some folks, Superior Bassworks (SBW) Deluxe "Dirty Guts" strings are respected and well liked by a lot of RAB, PSYB and roots players. Depending on the bass, depending on how it is played and setup, and depending on how it is mic'ed or amplified, they can actually play and sound decent, even compared to real guts.
Even though SBW Deluxe Dirty Guts cost significantly less than $100US for a bump set of 6 strings, they are just as much real double bass strings as the most complicated synthetics or steel strings. The point being, they are made from available raw materials just like the next company's strings, and they are made for and widely used on double basses. Just because we may not be in the target group that loves and uses a brand of strings doesn't mean they aren't real double bass strings.
For the OP (who has been using SBW strings), while I am not strong on RAB, I do slap, pizz and occasionally arco for mostly roots genre. I use SBW Deluxe Dirty guts D and G over Innovation Silver Slaps E and A -- I've tried other string sets and mixes, and keep coming back to this mix. The Dirty Guts D and G are strong and clear and mix well with the SilverSlaps E and A for tone, volume and touch, and for those who care as I do, they bow surprisingly well.