Welding headers

Hi Id like to weld my own headers for my 500cui 400 B-block 440-1 heads. 72 Satellite, manual steering, mopar ministarter. Id like to build some step headers from 2 1/8" to 2 1/4" and 4" collector.
Are there any things to consider. How long should the 2 1/8" primary pipe be? How long the 2 1/4"? Which bends being used? Should I route them like TTI headers or are there better flowing ones?

Thanks, Chris

Send me a pm and I can run your engine thru my header
program.... I'll need some data from you