First time 2cb questions

Hey everyone, I just got some 2cb recently and planning to take it with my girl soon.

Just a couple of questions:
-I've done LSD and shrooms twice each, pretty experienced with MDMA , ~135lbs , would 20mg be a good dosage?

-I enjoyed the high on MDMA much more than the trippiness of LSD/Shrooms. However, I've always wanted to combine the two so I'm thinking that 2cb would be a good start.
-My girl has never done psychedelic; however she does smoke weed and is experienced with MDMA. ~110lbs , would 15mg be too much for her?

Thank you! :)