My Duometre came with a sketchy 22mm strap shaved a mm to fit so I haven't had a chance to try to original strap in good shape.
The boutique had a solid selection of custom leather options (I went with a midnight blue) but customization is relatively limited to material and stitching color and pattern, and length. Other than those options, they are going to make it to factory specs, probably outsourced to Camille Fournet. 12 weeks is crazy though.
I'm going to see if I can also get a black over blue double folded edge strap ala EL2 made for something more modern and casual. Might look silly but you never know until you try.....