Whatever you do you should declare your migraines. Remember they will be documented in your medical history which the caa can gain access to in certain situations. This whole subject has been discussed a few times on here already with several useful pieces of information - try a search.
I suffered migraines and obtained a class 1. It did take an additional consultation with a neurologist but in the end it was ok. I still believe the fact I was honest and up front with them helped my case, and if at the end of the day they decide not to issue a class 1 it is for a very good reason... other peoples lives!