I wouldn't up the Vmax day to 80s or 90s unless you plan on making them sprint-float-sprints. 80-90m is definitely not Vmax work and you certainly wouldn't be able to do more than the first 2 80m reps at top speed. After that it would turn into an almost completely speed endurance workout because of the effect of the accumulated fatique on the succeeding reps. If you keep the rep length to 60m then you'll actually be able to get in a greater volume of work at Vmax because fatigue won't be so high. Having said that, if speed endurance is what you want, then there's no problem with 80-90m reps.
Also, as I mentioned before, I'd recommend putting the cleans first in your weightlifting routine.