Cross-post; clearance problem installing sound decoder in Athearn GP50

I posted this in the General forum, since my main consideration is a physical problem of clearance, not a DCC wiring/configuration problem. I thought perhaps people only look at the Electronics and DCC forum?

Post in MR General Forum

Feel free to flame me if you think I either should have a) only posted here in the first place, or b) not cross-posted. [D)] Both are valid points, I’ll admit up-front.