Angle of the engines, , ,

I'm almost inclined to think that it wouldn't make much difference.

With the engine say, , , 7" or something down in the nacell:
- the intake comes in straight,
- then the exhaust gets kicked to an angle by the engine.
- there's some degree of swirling action down the rest of the pipe.

Although there's no fixed stator's down the tube, I think the general exhaust flow is still going to want to straighten out to some degree because of the pipe length and the inherent swirling effect.

I was think along the lines of maybe a small deflector of some sort at the very end of the pipe.