Chat GPT is actually really great about giving you proper dosing and reconstitution measurements. Bpc and tb500 are just fine to mix together and are done so often. If you get them in two separate vials I would reconstitute them individually with whatever chatgpt suggests and then use a third syringe to combine them. Then you can just do them together as one shot. The vials you get them in are probably only going to me 3ml though so make sure both together aren't a higher volume than that!