150/170 should easily fit in the usual away section, and in the current weather conditions I don't expect that many to attend.
The issue is that the normal away end holds 202. If Stockport say 170 are coming, BUFC are going to play it safe and move them to the Town End, just incase 203 turn up. They haven't had a home gate below 2000 this season, so it's not unheard of for 10% of them to travel, especially as last season it was a midweek game.
We might well be seen as the only other 'proper club' in this division to them, and they know that the facilities are better than you get at North Ferriby, Brackley, etc...