Light in left hand?

[Chris H]

Ok Dean, I'll bite.
Your description of the light routing is correct.   The canister on the right, and the  Goodman on the left.   There are several reasons for this.  OOA not blinding your buddy is one.  Your bottom timer/depth gauge is, or should be, on your right wrist, it is pretty difficult to read inside a wreck or someplace dark if you are holding the light in your right hand.  You may argue the SPG is on the left, how do you read it? That is true, however we all know that is the backup SPG and the primary one is between your ears .  You should have a pretty good idea of your air consumption because you know your SAC rate and you've planned the dive.   I try to check my gauge every 5 minutes or so to see that things are going as planned.  If there is an isolator closed or a leak of some sort, you should be able to notice this on your checks, especially if you are deep (Not on Air you strokes! ;D  I know you love that word!).    The 3rd reason I can think of off of the top of my head is that the light will be in the left hand while scootering.   I don't have a scooter, but the idea of DIR is that you build on what you have learned from the beginning, and everything stays the same from day one.    None of the convoluted ideas about having multiple set-ups for wreck diving, deep diving, cave diving, or whatever.

As far as the neat and trim goes, if you are nice and horizontal in the water, and we all are :, that 3/8 cord tight up against your chest will have much less drag than the 18 or so d-rings on the typical convoluted Tech BC.