As said above, you need the biggest saw you can afford. Not saying you haven’t, but until you actually mill, you won’t understand how slow and difficult it will be.
$700 for a new 462 with bar is absurdly cheap. I’d jump on that deal and get another saw for milling.
The M-tronic system doesn’t tolerate higher oil ratios well. It can make the saw run funny and can actually lean the saw out from the computer not being able to compensate for the increased viscosity of the mix. I had it happen with a ported MS261CM with Motul800 at 32:1. If it occurred while milling, I would have not heard it and smoked the piston. I usually run 24:1 for milling with a 36” bar.
Milling is the only place where you do need the biggest saw. As said above, a truck and not a sports car. The best affordable milling saw for any real use is a Husky 395, and that’s coming from a staunch Stihl aficionado. They have better oilers and an outboard clutch that keeps heat away from the PTO bearing and seal. You can buy an adapter to run a Stihl bar on one, but I’m pretty sure you need a few extra DL on the chain for the swap. Do a muffler mod, DO NOT get it Ported, and run higher than normal oil ratio with the saw set rich.