I personally find bk-2C-B to be absolutely lovely. Really nice smooth come up, kinda reminded me of Methylone but with a bit more oomph. Very fuzzy and loved up, then the visuals kicked in about 2hrs in (maybe more, maybe less I couldn't quite tell as my perception was getting gradually more twisted the more I came up)
The actual visuals themselves were immense, lots of patterns dancing, tracers, stuff warping, amazing C.E.V too, I was getting synaesthesia. I was really impressed by how much (IMO) it actually mimics 2C-B but with maybe a little less intensity. Horses for courses though I suppose and some people obviously aren't experiencing the intended effects for whatever reason. I really rate it tbh.
On topic I have taken bk-2C-B with both coke and e.p.d crystal in the same night, I'm here to tell the tale but I wouldn't recommend it personally. I did have moments where I completely had my breath taken away from me and was rushing my back out! I was able to handle it without panicking but in hindsight shouldn't have sniffed as much powder as I did that night.
I think if anything maybe take a little bit of coke now and again during the trip if you find you're experiencing a heavy body load or anything.
I found it to be pretty energetic on its own but after 6ish hours the body load starts to come and go and the rushing gradually subsided. Me and my mate both managed to sleep pretty easily surprisingly (e.p.d or coke alone make sleep difficult for me if I've had a session, tryptamines, 2C's and the like even more so)
We must've got about 4/5 hours kip and both woke up still experiencing some pretty vivid visuals.
All in all I like it a lot! Don't think e.p.d and bk-2C-B are a healthy combo at all though having tried it myself. We also snorted a load Diphenidine when we came to get our heads down..... Things got very colourful and then I think we just anaesthetised ourselves cos next thing I remember is waking up.