So, when I have the camera open with full bellows extended (it being a draw-back camera), basically it is the length of the full bellows extention from lens board to ground glass?
No- focussed at infinity will require minimum bellows draw- then measure as Ken said. If you had the bellows fully extended you would be focussing at something near, i.e. close to if not at or beyond 1:1 (macro/close-up)
If only we could pull out our brains and use only our eyes. P. Picasso