what i was actually thinking may work,
it to adjust the straps before putting the kilt on so that they are
fastened correctly but as loose as they can go with the belt in the loops but unfastened,
then either stepping into the kilt or pulling it over my head as one would do with a sweater.
this would aid in keeping the shirt tucked in correctly,
and once the kilt is in place tighten the straps for a correct fit and secure the belt.

it may sound unorthodox but I'll bet I'm at least close to what I'll have to do.
funny thing,
I'm a DRUMMER!!been playing since i was age 6,
and boy are my arms tired.. buh dump bump!

i do actually have partial function in my left arm, but it's not very strong and
the movement is not... uh... natural.
it took 15 major surgeries spread over 6 years then another 5 years therapy to get it to where i can really function on my own.