Somebody is pulling your chain, to start with the standard stroke on a 350 chevy is 3.48" not 4.00" ..... the stock bore is 4.00, now it's 4.060. The .045-.065 rings are the gapless type which you really don't need if it's for a street car .....unless you just have to have them and don't mind spending the extra money. What is the engine going to be used for and whats the rest of your parts combo? You really have to think this thing out completely before you start buying parts, they all have to work together.
You can get standard ring sets in .030, .040, and .060 just about anywhere. BIG difference in price, look at www.Summitracing.com
or in their catalog on page 140. Sealed Power / Speed Pro, Hastings, Elgin or Summits etc. I would get the moly faced rings (not plasma moly) and your piston ring lands will dictate whether you get 1/16 or 5/64 size.