The weight in all of the modern steels is so small that unless you are comparing the lowest end with the highest end the weight difference is hardly worth mentioning. And even then there are no free lunches. One of the reasons that everyone loved the ride of Reynolds 753 was because most of the tubes were straight gauge.

I had a Bottecchia built from straight gauge Columbus tubing and you could actually tell that it rode better than the butted bikes. Apparently the tubes flexed more linearly or something because it felt very similar to a titanium bike.

So going for minimum weight costs you ride comfort for what that's worth.