Yes, you can convert VO2max to HRmax percent because VO2 max and HR max has linear correlation at least until you reach close to 100% of VO2max.
The generally accepted formula for conversion is as follows:
%MHR = 0.6463 x %VO2max + 37.182
But it's a bit harder than that because fiber recruitment also depends on the fitness level of an athlete and while elite athlete can cruise at 65% of VO2max on recovery days, an untrained runner would need to keep under 50% of VO2max not to recruit type II (FOG) fibers.
The same only vice versa applies to workout days. While for an untrained runner it's necessary only to reach 50% to start recruiting type II (FOG) fibers, an elite athlete would need to push to 70% of VO2max before even any type II (FOG) fiber unit is recruited.
So basically this is how to think about training principles:
With type I (ST) fibers it's an easy game – they are always recruited at any speed and peak motor unit recruitment is reached depending on athletes level of fitness with maximum number motor units recruited at 63% VO2max / 78% HRmax for untrained and 83% of VO2max / 91% HRmax for elites. As you see the ST max recruitment falls very close to the generally accepted "anaerobic threshold".
Type IIa (FOG) fibers initial recruitment happens at 51% VO2max / 70% HRmax for untrained and 67% VO2max / 80% HRmax for an elite athlete. This is the intensity I call the borderline grey area and you need to keep below this threshold at all times during easy/recovery runs. Never ever go above this on easy runs or you will compromise recovery of fast twitch fibersthat you wan't to save for workouts/races.
Type IIa (FOG) fibers peak recruitment happens at 76% VO2max / 86% HRmax for untrained and 100% VO2max / 100% HRmax for an elite athlete. This is the intensity at which peak fast twitch motor unit recruitment is achieved and going above that will cause only pain but no significant functional benefit regarding developing aerobic endurance. You can still go up there for short economy repetitions and speed work.
So bottom line is – run easy on easy days (never above 70-80% HRmax depending on your fitness level) and run hard but not too hard on workout days.