@Cuz The technical answer to finding Z2 is knowing your upper aerobic threshold and creating your zones from that (most would suggest aerobic threshold to -10% of that number = Zone 2). That's likely going to be higher than the percentages ranges you point out above (which you nailed, by the way...that is what is typically suggested).
One thing to keep in mind: the bpm data points are more 'good ideas' than absolutes. There is a HUGE continuum that exists in this.
For example, I'm guessing based on your calculated max, you're assuming Z2 for you is between 106 bpm and 124 bpm. It's good to remember that your body doesn't stop developing the favorable outcomes found with Z2 at 125 bpm. It's still there.
There is a much larger continuum that exists than the imagery painted by (insert your favorite Z2 programming). Spend most of the time doing long and easy training (high volume, low intensity). Sprinkle in a few hard days. Adjust both of those up in incremental amounts over a long period of time ("periodize" and overload progressively) and give yourself the opportunity to absorb that volume with recovery weeks.
I use my HR as information, not a master. If I feel good at a given pace, but notice my HR has drifted in the low Z3 range, I don't slow down. I say "interesting..." and keep trucking. On the contrary, if I see my HR on the upper end of Z1 and feel smoked, I don't force myself to go faster. I say "interesting..." and stay at the pace or slow down. Once done, I might use that data to adjust my programming (give myself a recovery week if Z1 is torching me, for example...).
That's probably more of an answer than you bargained for, but I hope it helps!