And then there's the impossibility to build your chassis 100% flat, true and accurate...build your chassis and then attach your suspension based not upon the chassis, but upon what it needs to be...
Sound observation and advice, carguy. The chassis is a meta-bracket that keeps all the components flying in formation, but the only components where precision position really matters are the suspension brackets. I favor welding the suspension brackets on the chassis without clamping the chassis to the table--if you have to clamp it to the table to get it flat, it's going to sproing back when you unclamp it, and the brackets will sproing out of alignment in sympathy.
So, build yourself a nice chassis, and if you use the tips on the previous pages, it'll be more true than the chassis the robots weld in Detroit, but it won't be perfect. Then add the suspension brackets; either way would do, but I start with the rear brackets, and then position the front brackets in reference to the rears.
If I were making mass quantities of chassis, I'd make a fixture out of I-beams that would hold all the suspension brackets at once. Then I'd drop an otherwise finished chassis into the fixture, and weld the brackets to the chassis.
BTW, the reason the Kinetic standard suspension brackets have their 1/2" hole .050" off center is so a builder can make a subtle hole position adjustment ( .100" +/- relative to the other brackets) by flipping a bracket over.