I would suggest the inner sleeve gear bush is best drilled before fitting and finishing to size as the lubrication holes through the gear are at an angle to the axis of the bush...Consequently, it's very easy to snap the drill as it breaks through the bush....Oversize holes can be drilled in the bush to ease alignment when the bush is fitted...
The two similar gears on the shafts differ in that one is drilled and the other isn't...The undrilled gear is fitted to the mainshaft as it is lubricated partially from the hollow shaft...The drilled gear goes onto the solid layshaft and is lubricated via the holes through the gear/bush...Care should be taken to fit the respective gears in the correct positions...Ian
Thank you for your thoughts Ian, I'll see what happens.
Drilling the bush will double it's price especially as they will be made in very small numbers.
Then you have to consider the skill required to line it up.