I usually snug it up with my impact wrench. Just make sure that the sides of the washer are bent up to keep the nut from spinning.
Interesting story...I was removing the clutch basket from a bike and I used a 3/8' ratchet to loosen it up. This was before I got an impact wrench and I was all set to hold the basket from spinning and the nut just spun off. I could have removed it with my fingers. It hadn't been removed since new so it was like that from the factory. I figured there would be all kinds of wear so I throughly inspected everything. I couldn't find any problems.
The bottom line is as long as there is no axial play in the basket (in doesn't slide on the shaft at all) then your set. I still tighten up good to make sure everything seats good but as long as the washer has prevented the nut from spinning, it will stay snug.