seat allocations

i'm travelling from MAN-BGI next sunday (16th April) and i went on the VS web-site last night to allocate our seats, the plan showed that there were only around 35-45 seats un-allocated and there wern't a single 2 seats together, does that mean it's guaranteed we'll all be seperated in the flight or if we check in 3 hours before will be all be seated next to each other or near each other? also does anyone know what aircraft is likely to operate this flight? 'the what aircraft will i be on?' feature doesn't say!