How much info, that's hard to say, rather general, better ask a specific question and I will try to answer it or find the information.
As a minimum I could go through the Bulgarian military aviation forums to see if I could find any information that you need, but I currently do not have.
There are dedicated topics with discussions for each aircraft that was used by the Bulgarian Air Force.
As for stencils, each aircraft is marked with standard factory stencils, meaning Soviet/Russian aircraft bear stencils in Russian, while our PC-PM, C-27J and AS-523AL are marked in English.
For Floggers, we had several painted with a shark mouth, a very cool scheme:
It is an UB Flogger on the pic above, but some of the single seaters MLD had that too and I think I could help with decals for it.
As I said, just ask a specific question or place a specific request and I will try to help.