A few thoughts on this one:
1. CRA is a good way to get T4s if you don't receive them. That being said; whenever you move or on an annual basis take the time to ensure that your address is up to date in RPSR or CCPS (pay systems) and that your pay information is correct. This is often a problem and still doesn't guarantee there won't be some hickups.
2. Class C pay can be administered in RPSR, TF authorities and the broader pay management authorities are not yet keen on allowing reserve units to input class C contracts. I've been deployed using RPSR to administer my Class C, it meant my transition from A to C and back was flawless. Frankly, we should be dumping the onerous conversion of reservists to CCPS for deployments and doing it all in RPSR. It would take an equivalent amount of labour and save huge problems.
3. As with everything, get and keep copies of everything! To get your whole pers file you have to submit an Access to Information Request, but if you've got most of it your OR should allow you to photocopy a handful of docs here and there. This has saved numerous people whose pers files have disappeared in the system.