From https://irsa.ipac.caltech.edu/data/UCAC4/ucac4.html
UCAC4 is a compiled, all-sky star catalog covering mainly the 8 to 16 magnitude range in a single bandpass between V and R.
A2.0 also goes down to 18 and includes mag 4 and fainter. If you are doing OK with B1.0 then that's good.

I still think you should start with Astro-Physics and see if you are getting the performance that it can provide mechanically and with APCC.