Hi there is plenty of information on the internet, and you could do a lot worse than speaking to your local bearing stockists.
plastic cage bearings are cheaper to make, however they are very good at tasks they are designed for – including running quieter- however some materials can be degraded by heat and contamination (oil and combustion products),
C3 and C4 are bearings with larger operating tolerance than normal or “CN” bearing.
in the main bearings for example they allow for expansion due to heat – C3 having more clearance than CN and C4’s have more tolerance than C3 – and again the operating requirements for the bearing may demand the more clearance that a C4 provides –
I always tend to use recommended bearing types (C3 C4 etc.) however I am old fashioned and I view metal caged bearings as of being better quality.
some eastern block bikes used to have less balls or rollers in than western made bearings ( because they were cheaper to make) and this is what lead to a lot of bearing failures
so in short do some research on the internet and ask someone who knows about bearings and don’t forget YOU GET WHAT YOU PAY FOR
sorry I cannot provide a definitive answer however if it was my bike and I could not get advice from someone who knows what they are talking about – I would use what the manufacturer recommends