OK, let me walk you through my thinking when I moved up from a Barley Crusher driven by a power drill

)) to a Monster Mill 3 driven by an All-American Aleworks motor.
I hated using the drill and I was only crushing maybe 12 pounds of grain, not 7 times that much. I also didn't like that the drill didn't have enough power to overcome a standing start, so I had to really crush faster than I wanted to.
Did some research on options and alternatives; I think there are probably 3 or 4 excellent higher-end mills; I knew that
@Morrey had a MM3, and decided that the 3-roller was a better alternative for me than a 2-roller.
I also wanted to slow down the crush. I don't know how fast my drill was going, but it was FAST. The All-American Aleworks is 180rpm, which really relaxes the violence with which the malt is crushed.
That said, it's pretty darned fast anyway, as the pre-crush of the first roller and the wider rollers allow for that. I can do 12 pounds in about 2 minutes, so 85 pounds would be....roughly 15 minutes?
It's hands-free once the malt is in the hopper. In your case, I'd want some sort of chute that would keep feeding the malt in, and certainly there'd need to be some larger vessel to hold the grist. Maybe you could crush right into the mash tun?
It's not a cheap solution--I'm into this for 5 Benjamins, not including the cart I use. But it is the last mill I should ever need, and given that I'm trying to implement LODO processes, a slow crush and crushing JUST before doughing in are two of those processes. This lets me do that. Plus, whiel I'm doing 5-gallon batches now, I just bought a 10-gallon conical fermenter in anticipation of going to larger batches.
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There are other alternatives. There is a motor that is $100 less than the AAW motor, though if you're nonobrewery you'd probably want something more heavy-duty.
Some people are getting 1/2 horsepower drills from harbor freight and mounting them on a cart to drive a mill. It's hands-free and certainly less expensive than the AAW motor. The only question would be whether you can dial down the speed to your needs.
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If it were me, I'd put some money into a good mill first. If you already have one, then it's a matter of getting the right motor for it.
https://allamericanaleworks.com/
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My 2 cents. Good luck!