You got me worried.. I'm beginning to wonder if the position , vertical or horizontal makes any difference in how well the master works. Your's is vertical as in the original position, mine are horizontal. At this point I'm keeping my fingers crossed there's no effect on performance ! If so? I'll be back to the drawing board with alot of wasted work. I do know that in the vertical position, removing the plunger then filling the system through the master makes the bleeding process so much easier. Those particular masters are notorious for trapping air.
Boxing in the master would probably be a good idea. looks like a good candidate for getting some leg meat. Road signs are a good source of sheet material for such things. By no means would I ever advocate riding around in the middle of the night with a battery powered saws-all.
Very illegal! I'm just sayin....