So, up until now, I've only used Martin Lifespan 13-56 on this D-18.

It's a fine example of a Martin D-18, crossing the pond, different climate, never had any work, and yet action and intonation are perfect.

It leads me to believe it's not one of those twitchy b's affected by the least little humidity/temperature changes, and that the neck is pretty stable. So, bearing this in mind, would a drop down to 12-54 require a truss rod tweak?

Cheers
-F