Just for reference, here's where I installed my compressor. It's on the driver's side, next to the clutch master. Agreed not much room in these old trucks..
ExCabSwab:
Your setup is similar to mine, except I wanted (or chose) to install the compressor on my passenger side fender. I wanted to keep the wiring and hosing as short as possible, and at the time this seemed like the prudent choice. In looking at my engine compartment, I'm not really sure I need the adapters anymore as I was able to clock the pump enough so that it clears the hood.
I ended up rotating it 45 degrees clockwise so it is now facing the upper intake which seems to have cured most of my clearance concerns. Despite that, I went ahead and ordered 2 of Marlin's 90 Degree Exhaust adapters, just because I'm curious if they will work (and extra clearance never hurt anyone). If they do work, cool, if not, I'll just use them for redirecting the solenoid exhaust.
Here's where mine is currently installed (before rotating it):
