Ha, ya I might have said that kind of all over the place. (thinking out loud)He cant locate the center section as needed for optimum drain angle (assuming all the hoses clear), and then arbitrarily rotate the compressor housing without changing the drain angle?
I think you actually explained this in your sentence but for some reason I cant compute it.
The compressor housing just spins on the center section (once you remove the dowel pins) so you can only gain by moving the small section of the snail to the firewall.
The center section and turbine housing have an off-set if memory serves. So when you spin them, you can get the center section to move slightly closer or further from the firewall. Since the oil drain Must be in a certain position, one can only hope that it IS the position furthest away from the firewall.
So, IF that made any sense (lol) "signs" should spin that center section the way it needs to be, before making any more measurements. (it may change things)