243 took this category with the thickest casing and biggest crown w/crown guard followed closely by Deepsea while Iwc is no match against the big boys with no crown guard and the thinness among the three. The 243 has the 1000m markings on the crown lever while the Deepsea has the famous Crown signature. The Aquatimer is the interesting one with the old fish logo, apparently used before Richemont took over Iwc.
Thickness-
243 18mm
Deepsea 17.68mm
Aquatimer 14mm