Tower postings depend entirely on the need at the time. Towards the end of the course you get to make 3 preferences to where you would like to go, that however doesn't mean you will get one of those. Some people are lucky and get their first preference, others aren't and get the exact opposite. If you are worrying about location, tower isn't for you then. If its not a huge concern, do tower, work hard at it and then worry about your posting. If it is a capital city that you want, prove that you can handle the traffic/workload by doing well in the college. If you find the college hard, the field is even harder..just my 2c