I realized I never used the rests that sit below the steering grips on my catrike.   When I tried resting my wrist there I noticed  I felt like I was pushing partially from my shoulder blades that I hadn't felt before.   Presumably despite that my shoulder blades touch the seat when I'm holding the steering arms up near the shifters,  maybe that position is hunching me forward slightly.  
 
I'd only ever though to try using those rest because I've had some soreness in my right arm that I thought might be related to vibration transmitted through the steering grip on the catrike.   There's enough vibration there on my usual weekend rides to often require stops to reattach mirrors.  And it seems to be worse on the right side, likely due to both the crest of the road and sitting slightly off center.
 
I guess I should try readjusting the main grips back a bit.