All I can tell you is how I started with ACG - buy a used one to get a feel for what you think you might want. I bought an ACG Graft Recurve 5 from @Black Coffee of this parish... Actually I loaned it from him for a few days with a view to buying it... And transferred him money pretty much the same day I was that impressed with it. (I don't delieve in "signs" so much but on my way home from picking up the bass there was a pretty clear one as I was driving behind a Jeep Cherokee with an odd numberplate "xxxx ACG" - TRULLY BIZARRE!)
Anyway, living with that ACG for a while taught me what I like about what Alan does.
Zero radius fretboard - love it
Neck shape - love it
Scale length (33") - could be longer. I was used to playing Lakland 5s at the time so matched their 35" scale with my custom
String spacing - OK @18mm but could be wider, went with 19mm but adjustable.
Pickups (singles with an odd placement) - sounded great, especially the neck pickup but wanted twin P pickups and fatter enclosures. Ended up with a mix of Alnico P at the neck and reverse Ceramic P at the bridge. Alan was great with suggestions in this regard.
4 way selector switch - nope I had that on a Dingwall and didn't like it. Went with the all dancing 5K pre - this is the only thing I'd change if I was going again, and only because I've now owned a bass with the ACG version of the East Retro-P!
Recurve body shape - yup, like it a lot.
As for wood choices, I had my own ideas about what I wanted and Alan didn't dissuade me. I also wanted my pickups in a non-standard position - front pickup in normal P position, but bridge pickup as close as possible to the neck pickup. Worked well for me and the resultant bass is a dream!
I've had 4 ACGs now, the original Graft Recurve 5 (gone but served its purpose well), my custom 5 Recurve (I doubt I'll ever sell this one), a custom 4 Recurve (similar spec to my 5 string, regretfully sold), the 4 string Finn "cricket club" bass (sold, regretted, bought back). Not a bad bass among them to be honest!