I should've put it in a different way. The general opinion (based on research only) it was how 400mg/week is the "perfect" dosage, where gains are good, in good balance with a minimal exposure to nasty sides.
You are right in one way. When looking over the boards a general feeling is 400mg of deca is more than enough. But like many subjects this is wrong. Reason being everyone is different and there are so many inventive ways to do things. Steroid usage is so different all over the world.
Anyway in regards to your question I would simply start off low and then move up. If you have done 300mg before maybe look at going to 400mg. No need to just jump up to a high dose if you want to do it. It's all about growth phases. If your taking a decent amount of test I would say 400mg is a nice amount of deca. Incidentally if it is just for joint protection a dose of 100-200mg of deca is perfect.
One of the reasons (there are many) that western bodybuilders have a totally different look to eastern is the hugh amounts of test. Middle eastern bodybuilders very rarely use test... generally speaking I think their physiques look alot better than the US guys. But of course the US guys are complete freaks and much bigger (waist included).
An insight into things. My next cycle is gonna be (working up to these doses over time)...
Deca= 800mg per week
Test C= 200mg per week
Proviron= 25mg per day
Kickstart tbol or dbol for 3 weeks at about 60mg per day