I hear a lot of talk about the time & trouble of setting up certain chronos.
** Dr. Oehler & M D tell us that chronos give better accuracy with 'farther' screen spacing.
>>> I mounted my screens EXACTLY 5 ' C - C in a 2X4 first then a 2X6 with S S III. No muss, No fuss, Doesn't take long.
I'm going to mount the IIIs flush with the top of the board, just haven't gotten a roundtuit.
I set up with the first screen 10' from my muzzle.
PIX for demo only.
Jerry