You said "I know exactly when to hit it" and that is the part the machine guys never want to hear. On that Mesa slab, what was your window between when the bleed water cleared and when you started floating? I run into the same thing here in Tucson and the crew always wants to jump on it too early because the machine covers ground so fast. If you wait for the sheen to go away and the thumb print holds shape, you have maybe 15 minutes to work with and the trowel guys are already spinning. Do you use a magnesium float or a wood one for that first pass, because that changes when you can come back over it. And when your partner got those burn lines, was he running the machine too dry or just pushing the rpm too high early? That makes the difference more than the tool itself.

Man, soft handshakes and asking questions first totally changed things for me too.