Then at least in your case I have failed to communicate my understanding of de Charnay's words. Of course, he is concerned that the young men he advises should demonstrate their prowess for all to see, but he also points out that many deeds that should garner the doer great glory remain unseen, or unnoticed, and insists that these deeds are also worthy. If you do some worthy deed, then you are better for it even if no one (except you) sees that.
And yes, Sir Geoffrey is more concerned with quality than quantity; or rather with a continuing increase in the worth of your actions. So a man who fights in the lists is worthy, but a man who rides in the joust has done a greater and more more difficult thing, and thus has done more. From here he works his way through going to war nearby, going a long way to a war, learning to run an army, or besiege a town, etc. Eventually he says that a Prince (by which he means anyone from Viscount up, it seems) who does not *have to* do these things but does anyway is the most worthy. His advice to young men-at-arms is to sign on with such a Prince's army and try to work your way up the ladder with worthy deeds. It is very 14th Century, and I abstracted the central theme only, seemingly omitting too much context.