74V, are you running 20S or something? At 12S (~50V, standard OPPG setup) that won’t put out 16kg on 22" and 120kV. Would need closer to 28" or 29". I believe the OPPG motors are 170kV.
Nice! What’s the ESC? That’s what I’d be worried about in terms of reliability. I had a look into 18S and could only find the Alien ESCs but they don’t have the best reviews.
Pushing voltage up is always better, 3x6S 14Ah in series would approximately match the Wh/kg of the current system.