Any Spector, or any bass from the Ibanez Ergodyne line is fantastic for slapping. If you can afford it, Warwicks are the Rolls Royce of slap basses.

Have you tried the Sterling? The neck is a lot thinner. I’m not exactly sure what the pickup selector does and how it affects sound, but that has been discussed a few times and can be answered with a search.

The Stingray was noted to me alright for slap too. However the Stingray had good sound but getting around the fretboard takes a bit of effort and to set the sound up from slappy to low and punchy takes a bit of time.