Prior to airport check in SQ don't even give preferential treatment to their own elites (PPS) in seating allocation other than position in plane (they may to the superelite Solitaires, I don't know). However, leaving allocation to airport checkin, I often have an empty seat beside me, but takes a big leap in faith for long sectors. You may ask at check-in and if there is space they may accommodate your request, although I imagine they wouldn't differentiate treatment of Virgin golds & plats (who would also be lumped in with KF gold and star gold), so you could have some competition. Have you seen the seating chart, whether full or not?