Cambridge Mature Applicants

Hi all, I am currently admitted to a university overseas and will be starting Year 1 in March. However, I wish to pursue education in the UK, and have decided I would be applying this fall as a mature applicant, probably into one of the mature colleges. After looking at the information available, I require some advice.

Firstly, is there a preference/advantage for applying by October or March? Any data on this would be much appreciated. Secondly, I want to check whether the following is possible: apply to Oxford by October, and then apply to Cambridge's mature colleges by March. I know it sounds like I am trying to be clever, but I simply wish to make the most out of this opportunity I have at hand.

Any and all advice and your experiences would be great!