how to tell if x is the bpm for your track, and not maybe x-1 or x+2, is there any way in which you feel differently in such small shifts? is it a different body feel? do you sway to click tracks? get the bpm just right to the sway? and not try to guess the sway at every bpm?
just use a tap tempo button, play it for about 8 bars while glancing at it periodically during that time, then that should give you an idea. then test it around there and listen to it for about 8 to 16 bars, then test some of the surrounding tempos. then just stick with it. because it will be kind of dicey to try to change it later, at least after any audio waves have been recorded