when I was making some bamboo shafts from planting stakes the ends of both sides of the shaft varied quite a lot from one shaft to the other and of course from the front to rear.
I was able to use some small o-rings slipped over the shaft (normally 2 with a little space between) to fill up the gaps between the shaft and the guide sleeves.
Sometimes I had to switch the sleeves and determine which one would fit the best.
Took a little messing around with each shaft but it worked pretty well.
With your shafts being uniform you should be able to find one o-ring size and sleeve size that works together and be golden.