I use either the 3/8" HFT $20(sale)pro air impact or the Ryobi 18v if fully charged.
I think the spec . on my commercial Toro , is 40-50'#'s/~500-700"#'s.
I agree, cheaterbars on Ratchets regardless of warranty is not safe. I often use my 3/4" ratchet(CM) w. a 3/4"-1/2"socket adapter on my truck repairs.
If you want a very good impact that will have hi torque, the Husky black composite 1/2" impact hybrid ~ $130 (FL pneumatic) is excellent(very similar to IR's gun); quiet, light, easily removes my F-350 lugs(175'#'s) that my CP 734 gun had trouble with. Lifetime warranty too, like Snap-On and about 80% less cost.
BTW I have never had the blade spin removing the bolt w. an impact w. my mower. It has a release brake on the blade.