I have heard in the past that the knurled axle is pressed through one of the Oilite bushings, distressing the bushing slightly but not affecting its function.
For the 2333 type, the 1 piece axles obviously have to be installed all at once, but with the 2343 axles, how about pressing the axle through the gear(in the truck), then pressing in the bushings, then the magnet & end plugs? I don't know how far the end plugs extend into the axles... will they bind the axle in the bushings?