I've seen a BM vest. It's nicely done, but cut straight down like a box. I would take it to a leather taylor and have it tapered to your waist measurement. I told cruzer, If I ever ordered a BM i would leave the sides under the armpits unfinished so I could get it tapered and finshed to my size later. My Ladysewforus vest was made tapered, but the back on mine is velcro, which allows me to make it tighter. As far as I know, your BM has accurate closures on the side, which is going to make it more difficult. I knew about the accurate closure when I bought mine, but requested the back closure to get a good fit. I didnt want my vest the be like" muffin top" coming out of my girth belt.
For the JP clips, put your harness on, put your vest over it, and see where the clips want to come out. Dont cut too high, or too low. If you cut too high, the weight of the pack will pull your vest back, tight to your neck, and untuck it from your girth. I have a piece of velcro at the bottom of the front vest and a piece on the inside of my cod to make sure the vest stays tucked in. Take into consideration the placement of your back armor and where those holes fline up. again too high, too low, is going to put pressure on your back plate. I cut and sewed the shape of 2 sideways rectangles on my vest. IT allowed a little room the move up or down as needed and it's covered by the back armor.