just one pointer, with that backing board on the caul, watch when you are heating the belly, as the heat deflects off that back board, and hits the back of the bow, an' you cant see that you are toasting the back of yer bow.
I have taken to drilling big( 1/2") holes on the backboard so that the heat can dissipate, and I try and run my heat gun more vertically and more from the closed side/backboard side- so that the heat is directed away from the backboard.
no one else seems to have had this problem on here- jus' me.
so its prolly operator error- but just watch for it.