I got a La Spezia too, mine is 26/24 black, I also put it on your sub's bigger brother Slytech Chrono Sub
and I agree that it looks--and feels--very nice with the XaMas style buckle.. yummy
Strap Culture is another alternative with their 'legend' series...
very thick, very comfy, looks waay more expensive than their sticker price, and the buckle is also like the XaMas buckle