Ive struggled with this myself - and where i have landed is if you are going to do full-on w/d/w, you should do at least the wet cabs identically...ideally all 3 identical but mostly the two wet cabs.
If youre going to do full-on stereo with fx, two matching cabs.
Everything will still work, of course, mixing different cabs/speakers...but as soon as you start thinking ‘oh since im gonna have multiple cabs, it would be cool to have different speaker options’ you are taking at least a little away from a ‘pure’ stereo image that is identical on both sides.
What i did was two matching cabs (for either the two wets or when running in stereo) - and im ok mixing in a different dry cab (same dimension cab but different speakers)....this gives me ‘true’, identical wet or stereo cabs if i want, while also mix and match options if i feel like texturing, layering, etc by mixing one dry and wet cab in stereo.
Just my .02 of whats worked for me