I have one the The sausage maker doesn't sell anymore.
Pretty sure it has metal gears and as many of these contraptions it is made in china.
Cant remember what I paid for it but it was a lot.
I think the #22 is the best option and anything bigger for the home is insane.
But a good #12 would be okay too just dont go into business with it.
As for reverse any motor with a starting capacitor can be reversed.
If it makes a clicking sound after you shut it off it can be reversed.
You just have to wire a switch that will have a forward/off/and revers on it.
Mine is a momentary reverse switch that doesn't lock in you have to hold it in reverse.
Next is hand lapping/polishing/honing the grinding knives and plates on a dead flat surface.
None of them are perfect and it makes a huge difference grinding.
Next dont forget to put the cutting knife in.
I did the other day and for the life of me couldn't figure out what was going on for a minute.
If you get a grinder get standard plates not some wild design you have to special order.
The plates I ordered for the Sausage Maker were off size a wee bit for my grinder and I had to spin grind them so one or two would fit.'
They should have fit but some how the tolerances were off, made in Poland.
Ran a bolt thought them chucked them up on the drill press and ran an 8 inch sanding disk spinning while the plate was spinning.
You wont cut that hard steel any other way.
Probably 6 thousandths is all it took.
My opinion you cant have too may plate sizes.
And dont forget to get a stuffing plate and tubes if you intend to use it to stuff with too.
They do make pretty good stuffers.
I haven't done it here but I have elsewhere.
Worth