25' Powerlock II, can't see MMs, they all look alike, always work clockwise around a room, copes are always on the left, if coping, except the last one with two copes, ordinary #2.5 wood pencil. I like to leave longer crown pieces about 1/4" - 3/8" long depending on length of run, long enough to correct a bad fit with the saw but short enough to bend 2/3 of the length tight to where it would go to check the cope or miter fit. Hate/won't use rasps, sandpaper or do any whittlin on a joint and won't use filler, always correct with a recut. Then I mark the crown anywhere while partially in place and put a matching mark on the wall. To get the final length, I just measure from that mark on the wall to the next corner, then from the matching mark on the crown to my cut. I Almost always use an accessory table and fence on the SCMS, the kerf in that fence and table shows exactly where to line up the cut. One thing I also do is make marks around the room where the bottom of the crown should go and keep to that line, often I'll just put short vertical strips of white masking tape for making these marks on. Of course there are always rare exceptions but that's my preferred method. I probably wouldn't cope crown like your excellent picture, I'd bisect the miters, If coping, I like a coping saw, 15TPI, teeth down on the push stroke, often turned 90 to the frame.