I think you should consider though - are you sure you don't want to do breadth in first year? A good breadth does exactly what it suggests - it broadens your knowledge and allows you to think from a different perspective, whether that be an linguistic, economical or philosophical one. I've done good and bad breadth subjects, but when you're studying a breadth subject that you enjoy, you realise how glad you are to get a break from all the science.
It's a feeling that's hard to imagine when you're on the outside looking in, but I think the balance of 3 science/1 breadth is psychologically beneficial. 4 sciences is a stressful workload, while having too many breadths at once - and I know someone who did all breadth one semester - is not desirable as you're spending less time studying for the career you're (hopefully) passionate about pursuing, and that will make you unhappier. Also, a lot of Arts breadth subjects have essays due at around the same time - my aforementioned friend was really stressed during the last week of semester.
Long post I know, but something to consider for everyone.