I did meltdown like 2 years ago and it was a bitch.
lunges, you will travel 20-30 ft because of the length you travel per step. when you do 20 lunges/10 per leg, you're not only taking one step forward, you're lunging which is probably more like 2.5 - 3 feet, therein don's rationale of 20-30 ft.
Puking, yeah, expect to fight back/swallow a bit of it.
50-60% 1rep max, probably about right if you want to complete the exercises in prescribed fashion.
Sucks after taking a layoff and being out of the gym. I'm going to be starting meltdown again in a few weeks.
Might even look at Turbulence training again from CB.