Can I reverse these gears??

[Lesterz]

The first, second and third speed gears are worn as per attached pics. It looks like I could reverse second (41 teeth) and third (35 teeth) speed gears. Is that possible or will it cause some issue I don’t need? First (47 teeth) gear has a hub slightly set out on the worn side so I guess I either live with it as is or replace it. None of these gears are available on Hoyes parts list anyway.
There is supposed to be a thrust washer between hi-low gear (51 teeth) and hi-low gear (28 teeth) but it is not there on my tractor. The shaft is 24 mm diameter and the spline that the range shift gear slides on is 30 mm. What material and thickness should this washer be?
Thanks
Lester from Oz

[winston]

Haven't been there, done that, so pure speculation you could reverse the two gears without problems. Spacer is 20x43x2.5mm.