Ken, I read the procedure and was amazed that cold rivets are used to secure the ring gear to the carrier on the C60. Comparing the cross section to the C15, it looks like the the relocation, or size increase (or both) of the heavier pinion support bearing didn't leave enough room for bolts to secure the ring gear! Talk about complicating maintenance on a wearing part.
The manual talks about using a 20 ton press, special tooling and the rivets specified in the parts list. And if you don't have access to that lot, buying the crown gear and carrier half as an assembled unit.
Since you have the bare ring gear and pinion as a matched set, have you contacted the supplier about getting the rivets? My take is they shouldn't be selling these parts without advice and parts on how to install them.
This has got to be a known problem. Have you searched on MLU, HMVF and
https://www.canadianmilitarypattern.com for an answer?
Malcolm