I would go for Adams. Better academically, students are very friendly compared to Cranbrook, better activities for the boys. My son loved Adams. We did not apply for Cranbrook after the school visit as the 6 forms we met were unfriendly. Also the town’s church with grave yard is inside the school and academic is not that good.
My son did not choose Adams as we wanted him to be in the South East
Yes, weekly boarding only and mandatory GCSE for a modern language.They no longer offer Y9 places like before( they use to take 6 day & 4 boarding for Y9 entrance). So now they will only take if a place is available. Per local mums in the past a few boys will go to Eton so they will leave end of Y8.
My son was choosing from Royal Grammer School High Wydcome and Reading School, and he chosen the latter after taster days of two days and one night. The former has excellent boarding house facilities and a very good Grammer school and not mandatory for GCSE modern language therefore many HK boys boarding there.