Well it all depends. I really like crinical's IEM target and he mentions that the bass on the N8 was out of control.

the bass on the A4S, is heavy at times, i do switch between the mx and the m15 often enough when the bass burns me out.

64 audio tends to be a bit bass heavy in general but generally balanced. If you are coming from something like a moondrop blessing dusk ... you will definitely notice it..

I dont think you will regret the a12t at all, but unfortunately if you want a bass response that extremely dynamic from the 64 Audio line up, the A4s or the Trio are pretty much your best bet.

But dont second guess yourself, wait for the custom to arrive, and enjoy and cry because man their CIEM are super comfy and its hard to go back to universals.