Eh cyclobenzaprine (Flexeril) doesn't hold much value for me personally- at least on its own.
Given the right dosage, it'll make me a bit sleepy, but that's about it. So if that's your only intention in using it, you should experience some benefit, but we're all different.
Zero recreational value, and (for me anyway) not very efficient at its intended purpose as a muscle relaxant.
As for the comparison to diazepam, yes they're both muscle relaxants, but they work through entirely different modes of action and present very differently. To say it has a "valium-like effect on the muscles" is highly inaccurate, more just a bad attempt at simplifying a drug's effects from a doctor to an un-knowledgeable patient is all.
As a side note, I would think you may wish to use caution (on your dosages at least) if using in conjunction with cocaine....considering the serotonergic properties they each carry....
Glad to hear you're a little less anxious, I don't recall ever having got that effect, but I'm sure there are some that do.
As for achieving sleep, I would think in most cases, that 20-30 mg (if that) would be perfectly sufficient.....but YMMV.
Let me know if I can be of any further assistance and I'll help the best I can.
Hope you can achieve some sleep and get to feeling better- be safe and good luck.
-PA