depending on body composition, he should be no more than about 4lbs overweight with a SS plate and a HP80. Total negative ballast at beginning of the dive will be about 15lbs. Offset that by buoyancy of the wetsuit, and you're not dangerously overweighted. For ballast calculations with an empty tank, it's about 9lbs. 3mm should be somewhere around 5lbs positive, so total of 4lbs overweight. Yeah that's VERY overweighted
You can kick up 4lbs from the bottom, if you can't you have no business diving. Do the math before you explode about unsafe gear recommendations
Even these calculations are irrelevant and you know that. The determination of safety would be made when the suit is fully compressed and the tank is FULL. That is what the diver would have to kick off the bottom - NOT in shallow water with the suit expanded and the tank MT.
Even if the diver is strong and CAN kick off the bottom, it is still not safe!
Why recommend that someone DELIBERATELY over weight themselves with more ballast than they need and NO ditchable lead... all so they can dive somewhere else, with a different suit and be OK?
It would be far safer to dive without the extra ballast in freshwater and then add lead when moving to cold water ocean dives.
I personally dive with a negative steel tank, with a 2-3 mm suit, aluminum plate, zero lead and to be honest, I am heavier than I like, but it is reasonable. However, my BMI is in the obese range, I am diving in saltwater where I need another 6-7 lbs of lead (versus freshwater).
This is very different than recommending a new diver use a very negative tank in freshwater with a heavy steel plate and a thin suit. Don't you all remember the SB moderator who died not too long ago - simply because she was too heavy in like 12-15 ft of water?
Even Tobin, mentions doing the math.. but he does not actually do the math in this situation... Why? Probably because he knows it will not work out unless the OP is a very buoyant "fat guy". Not impossible, but I wouldn't make that assumption.