Fairly avid CK user, though I haven’t done any in a couple of years since getting sober from narcotics, up until 5-6 weeks ago when my use started again. Though, that’s irrelevant & I digress....
My main deal w/ Mr.Calvin Klein was usually for speedballs, but I would occasionally get a g or 2 and just do that by itself.
I hope that this helps as a sort of reference point, but when I was in the midst of my most frequent use, I was doing a key bump, upwards of 2x a keybump sized shots every 15-25 mins. In doing so, I could make a gram of pretty fucking fire scale last easily 12-16 hours. Would usually pickup in the AM, somewhere around 10:00ish, and I’d be shooting until at least midnight that night.
For me now, I wouldn’t necessarily worry about how quick I was ingesting it. But, rather all of the other variables at play. My concerns would be, how is my heart rate, how is my body in general reacting, what’re my veins looking like (not sure about you, but my arms would always be super fucked after a night, and especially multiple days, of shooting white), am I using sterile equipment, etc etc. Once all of those were checked and good to go, maybe keep a log on when, how much, how often, and how quick you go through your desired and most frequently bought amount. HAMS - harm reduction guide for alcohol moderation, strongly suggests keeping a long of your alcohol intake. I’ve never done it, but I don’t see how or why it wouldn’t work and be beneficial with drugs as well.
So, to answer your question, I think for me personally, a g a day or so (I'm factoring in 5-7 hours of sleep into the 24hrs). Best of luck to you man, & I hope I was able to at least help a little bit.