Given that there is no seniority to establish base allocation there are only two systems available. Merit (or arse-licking as grim would have it ) or pot luck as previously suggested. Having been sucessful twice and with a tongue as pink as nature intended I would suggest that it really is more important that you speak to the right guy on the right day rather than what you say to him. He is human like the rest of us. If he remembers you badly you are stuffed, if he remembers you well. . . Bingo. Safest option is that nobody even knows of your existence, but then you are totally dependant on random selection.