good advice, from Roger and also from Frank Ford via Spaw.

one thing Roger, the strap button on the heel cap wouldn't actually be under pressure from the case lid, there is sufficient gap there to accommodate the button without any adverse consequences. This may or may not have been the case in the older Martin cases, I wouldn't know.

as Frank Ford points out, one drawback to doing it as I plan is that the guitar would have a tendency to pitch forward, and fitting the button to the side of the heel would counteract this.

decisions, decisions ...