I care about his 40 time in how it effects his draft stock; so I won't bother debating combine vs. pro day times because both sides make compelling, sound arguments.
If Cam gets drafted day 2, I'll be targeting him between rookie picks ~10-16 depending on landing spot and when exactly he goes day 2. I still see an MJD/slower CMC as a ceiling, and in a PPR league that's something I'll always move ahead of RBs who can't catch/only catch dump offs. Other than lacking "speed", the most common criticism I hear on him is "he's hard to project/there aren't other guys used like him in the NFL outside D. Henry". That's an incredibly weak criticism to me, and doesn't really move my needle at all.
If he goes day 3 or later, he'll definitely be dropping down about a round+ for me. In general, the hit rates on RBs drafted in the 4th round and later are just abysmal, as much as I love Cam, at that point I do believe the odds will be stacked against him becoming a fantasy contributor worthy of a late 1st/early 2nd round pick.
TLDR, gonna let the NFL do the work for me on this one. But if he does get day 2 capital, I'm remaining high on a 3 down, pass catching, goal line punching, unreal contact balance, top of the class tackle breaking ability, unlimited effort/coaches favorite guy. Those are some of the most important RB check boxes for me, and he ticks them all. It also just gives him multiple ways of paying the bills in fantasy. Even in a committee he could easily be the David Montgomery putting in 12+ TDs with his 78% success rate on 3rd and short plays, 94.1 PFF grade on plays 3 yards or less (top in the class over the past two years), 23 TDs (also top in the class). It would still get you a low end RB1 in fantasy, despite a team being dumb and not taking advantage of his pass catching skills which are also at the top of this class.