Thanks.
For now I’ll just stick with the 40mm that are on their, as the profile and handling has been fine on these rims.
A small part of me wants to sell the new 43’s and get same GKSS in 38. While giving up some comfort on rougher terrain, that’s only 10-20% of the riding I’ll do on this mixed surface bike. I’m guessing the 38 would be better on pavement and crushed limestone rail trails...