I dont think it would be possible to open the terrace as it is only half the length of the pitch towards the away end and if there is a decent away support would they not use the catering at that side. I think I saw it open against Ross County, also are there not advertising boards on the terracing now?
And there couldn't possibly be 10,000 the capacity, including a full away end and west stand is 7,750 ish. That small part of terracing wouldn't add over 2k.
P.s If the league is won before the last game of the season then I don't think we would even need the West Stand to be open, as I dont think we will sell out the north and main stands.