Nose gear piston rod bushing

Looking for some input from you fellow nose wheel builders. The manual specifies "filing" the inner profile of the piston rod bearing (bushing) and shows a profile but provides not specifics as to final dimensions/fit. I could use some advice as to what clearance is desirable between piston and bushing, and how much taper is required. My initial effort has a straight bushing ID of 0.642 to 0.643 with just slight rounding of the two edges. There is more variation on the powder coated piston depending upon where measurements are taken along its length; OD of 0.634 to 0.640
So 0.002 to 0.009 inch clearance on the diameter.
Any thoughts and experience with this?

The build manual emphasizes that the rod should be able to travel its full length . I hung the gear with no rubber disks or washers and moved the gear up and down then filed some more until travel was OK. I found that the rod would make contact with the fire wall slightly before full travel.
As the gear pivots about the mounting shaft it causes the rod to prescribe an arc, hence the opening of the ends of the bushing is required. While doing the fitting one must be careful to not let the rear pointy end of the gear damage the fabric, as when the gear comes down the pointy end goes up and will contact the fabric

Thanks, I was hoping to have the bushing "good to go" before I pressed it into the engine mount, but your approach may be the way to go. Appreciate the reminder about the potential fabric/pointy end conflict too.