I’ll preface this with “ I don’t have a Wal” so I would listen to the dudes who actually own then.
I am, however, a guy who likes a variety of artists who have used Wals on a number of recordings. The bass will depend on the tone you’re going for and the artist your trying to replicate. I can get the Justin Chancellor tone with a variety of basses as long as you have an EQ or even better, high or low pass filters do some dirt.His dirty tones aren’t hard to “close enough” clean tones get a bit more tricky but , even then, you can get pretty close with EQ and effects. I usually don’t think body wood makes a huge difference but a mahogany body does add a bit of low mid honk that is kind of magical.
I really like my G&Ls to cop the super aggressive Tool , Rush or RHCP Wal tones. I have an old El-Toro with mahogany body and narrow aperture MFD pickups and an “oh, sh!t” switch that kills. That’s be my recommendation. Stingray would do for the more nasal aggressive tones. P/J is pretty versatile and would get you close enough in most situations. Honestly as you have a decent bass, a decent amp and some basic effects/pedals you can get pretty close and save about $8k