Does anyone know what the effective cap is for Knowledge/Sense?

I'm of course referring to the fact that they supposedly determine the recipes you learn for synthesis.

How high is the highest needed for recipes?
Is it a combined max or do they each have their own set of recipes to teach you?

I currently have about 270 Knowledge and about the same in Sense. Is there a need for me to try and reach higher?
Once I learnt the recipes provided at that level, can I get rid of all the knowledge-providing items and focus on other things?

Thanks.

Not sure what the cap is, but you definitely don't lose the recipes if you drop back below the value.