oriel vs st catzWatch
personally i like oriel better but seems like st catz is not that popular(?) so will i get a higher chance to get admitted to oxford if i choose st catz 🤔
As far as I'm aware for most (all?) courses you will normally be interviewed by a second college, and may be admitted another college through a reallocation system (either before interview or after). This system is in place to prevent applicants who are "Oxford material" from being squeezed out due to applying to an oversubscribed college, so they have as good a shot at the university in general.
If you specifically like Oriel, then your best chance of getting into that specific college is by applying to it. However that won't affect (in theory at least) how likely you are to get into Oxford generally.
BrasenoseAdm or LMH OXFORD might be able to shed a little more light on this?