Back a few years, most road bikes came with 53/42. Then 53/39 came along and I think it was mainly for those riding more mountainous areas. I have been riding a triple and, like you, find I often ride all day in the 42 ring if on flatter terrain (love my 28 small ring for really big climbs). My friends with compact doubles are finding (when riding on flatter terrain) they are often switching between rings and the ends of the cassette (big - lttle cogs) trying to find the right gear. I suggest you stay with the 42 and pair it with a 52 or 53 for those tailwind/downhill situations. I don't think 50/34 makes sense for your riding.