building custom headers tips

[abadsvt]

Hi guys! I was thinking about building a custom set of headers for my project. I have always wanted to build a set and decided that i should just give it a try. Any tips or a how to would be much appreciated. Is there a specific sequence to weld the primaries to the collectors? I have always wondered how the weld in the middle as the fit the primaries into the collectors. Does that make sence? Also what is the difference between 304 stainless and 409? It is going to be for an LS1 basically stock with a few upgrades but nothing crazy. I was thinking 1 3/4" primaries and 2 1/2" exhaust. Does that sound good? Thanks ahead of time.

Josh