I respect Mr. Colin and other's experience...
My 1999 AS has 'solid wire'... I have encountered some issues with metal fatigue in the wire... but, not everywhere.....so, that was my suggestion for multi strand.
Same with my boats, motorcycles, aircraft. Stranded run next to solid, solid fails...first. If it shakes or moves, I prefer stranded.
When I replace wiring in my AS, it is stranded....
Of course YMMV, it is YOUR AS...and we wish our all the best..
Peace and Blessings..