Ooooh, price is a good one!

349s are a good balance between size and speed - not too big, but pretty quick. 349s are to 305s what 451s are to 406s. Tires for 349s are meant to be skinnier since they are designed primarily for the go-faster crowd. If you want to add to your bike design, you can make it so that the customer has the option of swapping 349s and 305s - just make sure to design brakes arms that can accomodate both rim sizes.