"This is a large issue for me. At trail speed I can hear the CB (volume is always at max) but I have difficulty hearing the handheld - even when holding near my ear. For most any unit, I'd be looking to see if has an option for an external speaker (that could be mounted on the roll cage near my head / ear)."
I think it does. It has the same connection that Baofeng, and Kenwood use for external mic/speaker.
I think this one would work with it. I have one, loaned permenantly to my son, that I used on my baofeng. Its a speaker mic with an external speaker port. I plugged a bluetooth device to it and to my rollbar speaker and it worked pretty well.