DS2 is in Shells (Year 7): he gets roughly 20-30 minutes for the subjects he is timetabled to get homework for - that is 2/3 subjects per night. The English work is usually set over the weekend as it takes longer. That means between an hour to one and half hours per night. He sometimes takes longer if he is interested in getting extra credit.
DS1 is at a grammar school and I think he was getting something similar last year, so I am afraid you will need to face nightly homework wherever you go
I think they both started the year with homework taking a lot longer than we were told it would but that was mainly due to their dithering around between things and wasting time.
Hope you get a place at your top choice . You sound like someone who will do well wherever you go.