Depends on how quick you want out? Ok you have a 3 yr ROS but with all the resettlement and leave plus if you want to do ELC courses you could be out well within a year.
As you are a SNCO FC, you come under Ops Spt (FC) Officers desk, give him a call and see what the situation is regarding both the SNCO and Off FC manning. He may well 'know' something regarding future manning levels. Likewise if your current XO is happy to gap the post then he can deal with the desky to release you earlier.
But remember if you start to get difficult then doors will slam shut fairly quickly, its best to find solutions and do a bit of give and take.
Don't know why you want to leave the 'Tower of FC Power' anyway, get yourself in charge of some Klix Machines and you will be a WO in 6 years anyway