It almost sounds like you are trying to optimize a career path, rather than start a research career. If so, I think that's quite misguided, from almost any angle. If you aren't fundamentally guided by a passion for something in math, and make your choices on that basis, I doubt counting citations is going to help you.
In my experience, I've seen very few mathematicians focus on career path and come away happy and successful. Math research isn't a corporate hierarchy. Many of the most successful researchers I've known, just worked very hard, often for years in relative obscurity, pursuing an original program. The payoff came when they had interesting results, not when they had enough social connections and bullshit to fill their resume.
How do you imagine the number of times a professor has been cited, to affect your work? Are you hoping that you'll hitch to the bandwagon of a hot, emerging field?
I've known a few highly talented students who ended up with illustrious, Fields Medalist, advisors, where it probably backfired from a career view. The problem is that being a Fields Medalist doesn't mean being generous with students, writing compelling, or even fair, recommendations, having realistic expectations, encouraging or advising well, or being an engaged advocate. I'm sure most people who've sat on a hiring committee have read stellar recommendations for mediocre students with generous advisors, and mediocre recommendations for stellar students with arrogant advisors.