Hi, I want to build a triangular cupboard into the corner of a room, 1m sides, full room height. For studs on the wall, do I still just use 2x2 etc., or am I better off getting something with a 45 degree angle in it? Off hand I'm aware of 3in Arris rails which are exactly the right shape, but they're for external fencing, so tanalised, not planed etc. Should a timber yard have something specific for the job? Does it matter?