It really depends on how he is used. If he played consistently on a top line all season I could see 50 points on the top end. The way he's currently being used, lower lines with some time up with better players and some PP time, he could get 30'ish.
Btw, if you're ever interested in what we as a group think a player's stats will be, over the summer we did a stats projection thread. That would be a good place to look.
Not that I've watched Sceviour a ton, but I would think 50 points would be the kind of number he'd hit as a career high in a pretty lucky year and that he'd never come very close to again. If he ever became a top 6 guy I would be surprised, he always struck me as the kind of player who would be closer to 20-30 points every year as a good 3rd liner.