NO RTV!!!!
Use Threebond, Hondabond, Yamabond case sealant... same thing with different names.
The rings locate the bearings - fine to reuse and, probably, NLA anyway.
Check the primary chain slack: it's not cheap to replace but since you're in there it's worth checking. There's likely some wear pad thing for primary chain slack to hit: if it's badly worn then you can assume the chain has stretched too much.
Inspect the shift forks for worn tips or being bent. Again NLA but used good are better than bad ones. You can't really see the drum grooves without pulling the forks but the groove corners can get badly rounded and cause weird shifting problems too.
If you have a few bucks to spare, replace the sprocket shaft outer bearing. This one takes a beating. Only available from Honda (or CMSNL et al) as the groove is unusual. You can have a bearing shop grind a groove to match but that costs more than an OEM or NOS bearing.
The needle bearings are rarely bad, last forever unless someone has severely ignored oil changes. If you disassemble the transmission shafts you can check for damaged rollers or cages. Take pictures or something as they come apart, reassembly order is NOT obvious.
