sewups are a great feeling ride, but i think your first flat while commuting might change your mind. i'd rather carry a tire lever and tube, then a spare tire or a tube of sealant. tufos makes a sealant that i've heard works super well for fixing tubular flats, but i've never used it.
i think sewups are best for racing applications or for road bikes you ride long distances on and that aren't your daily commmuter. i would just get some high quality clinchers instead. i have vredestein fortezzas and some continental attack/force tires and they feel great like tubulars. very responsive tires. the fortezza's are the grippiest tires i've ridden. they're light and have a flat resistant strip in them. plus, the max psi on them is 145. i've yet to try them, but tufos makes a tubular tire with clincher beads. i'm intrigued.