Military Box Pleats: how much "excess" to cut-out of the fell?

[jhockin]

Well, I've finally finished sewing the fell and basting the pleats, in my first attempt,at military box pleats.


Shot at 2011-07-18
I've searched the forum, but the only thing I can find is warnings, to leave more seam allowance, than 1/2". I've also been told that the cut-out are narrower, than for a knife-pleat.
SO: can anyone who has done one of these tell me: how much seam allowance SHOULD I leave? 1"? 11/2"?? How much is too much? What is the opinion, of those that have made an MBP?