If you do a lot of hilly climbs but also have some flats I've found 46 x 16 and 46 x 18 (as flip-flop) to be pretty useful. The only thing you have to worry about with 46 x 16 is the 1 skid patch, but if you avoid skidding and save your knees, it's not a big deal at all.

46 x 19 is really low.

I ride 46 x 15 / 14, in Richmond, VA, some hills