To me it's like asking which is my favorite child. There's more to it than width. Tread, casing, etc etc. I stopped using tubulars late last century and always thought something subtle was missing. But I found that supple sidewalls made a big difference, I rode 23mm Michelin Pros for a long time on my Mercian on the advice of a former racer friend. Loved the feel. When I built my International I got Compass 36 (or is it 35?) lightweight casings and was super impressed by the quality of the ride. I didn't perceive any lack of handling or speed, unless I had them under inflated. Recently I fit 30mm Challenge Strada Pros on my Mercian and also find no loss of control or speed. At the far end, my Rivendell runs 42mm Gravelking slicks and is the fastest and most confident descending bike I own, and I've revisited tubulars with 30mm Vittoria Graphenes on my Paramount and PX10 and find them so be very similar in feel and roll to my other quality tires. Kinda like saddles, run what you like and enjoy the ride. YMMV.