Selwyn or King's College

I'm applying for HSPS at Cambridge and can't decide between Selwyn and King's.

I'm considering Selwyn because I really like how it looks, it's close to the humanities department, and all the first-years live together, so I will be able to socialise. Additionally, I could get three interviews, which would give me more time to express myself. However, it's not close to any convenience stores. Also, based on the website, there is a significant emphasis on academic achievement. According to the website, in the majority of cases, they set offers at a level above the University's minimum offer level, so my offer would be A*A*A instead of A*AA. I'm predicted 3A*s, but I'm scared about missing the offer, so this is a major worry for me.

On the other hand, I'm also considering Kings. Like Selwyn, I really like how it looks, especially since it's on the river. There also seems to be a strong political culture there. HSPS seem to be less competitive there, and they admit more students than Selwyn. Lastly, the location seems very convenient in terms of shops. However, it's relatively far from the Sidgwick site, I would have to do a written assessment, and the tourists would probably get annoying after a while. For the written assessment, I would enjoy writing about a topic I'm interested in. There are around 5-10 questions, so I'm sure there's something I would enjoy and be able to write about. But I don't know much about the assessment (for example, how it's marked or how best I should structure it), so that's a point of concern since I normally work best when I can prepare as much as possible.