Sure, whatever works.

In general, my mindset wants to regard personal customization as either a very last resort or a temporary measure. We're amazingly flexible, and I usually have faith that natural selection + received technique tends to result in average usable ergonomics and capabilities. I admit I like the idea of being able to pick up any standard instrument and play well without relying on non-standard gear or features - barring, of course, real physical limitations.
I'd guess that box players like Sharon Shannon and Josephine Marsh have smallish hands, and have figured out a left hand that works for them on the basses and air (when not ignoring the basses altogether).
Of course, it does seems to me that box position and technique tend to be all over the place from person to person, so "standard" may be iffy in box terms. Sharon uses what look like big foam pads on the left. Paddy O'Brien glued a big "thumb board" underneath his fingerboard. So I should probably shut up ...
But I'll try throwing on a left strap to see if that makes any difference.

Vivat diabolus in musica! MTGuru's (old)
GG Clips /
Blackbird Clips
Joel Barish: Is there any risk of brain damage?
Dr. Mierzwiak: Well, technically speaking, the procedure
is brain damage.