Don't know if this will help or not but here's a pic of the 4-link we built for our Gasser Coupe project, now deceased.
Is this the type of 4-link you are considering or are you thinking along the lines of a 4-bar like the late 'Birds and Mustangs use?
If you're going to go with a true 4-link then my best advice, based on personal experience, is SPEND THE MONEY. Don't cheap out and buy the 'best price' for a kit. That is what I did and by the time I was done I could have gone to Art Morrison, Chris Alston or one of the other top drawer vendors and purchased a complete back half clip and saved $300 - $400 off of what I eventually had in it.
I eventually sold off the Coupe parts (that I couldn't use) to build our Falcon and I had to total all of my receipts to come up with an asking price. Then I compared what I had in it, not counting time, to the same parts from Art Morrison. Sheesh!
The only thing I used off of my bargain $600 kit was the brackets and coil over setup. Buying a 4-link a piece at a time is easier on the wallet because you don't lay out all those sheckles at once but if you can afford it, purchase a complete clip (frame rails, rod ends, coil overs, etc) from one vendor like Competitiopn Engineering. Everything will be engineered for the next component and your overall fabrication time will be far less. You can then either fab your own housing and order axles to fit like we did or purchase a pre-built unit with axles from Moser, Strange, Dutchman, etc.
Sorry to be long winded but I feel strongly on this one.
Of course if you are going with the four bar set up then none of this applies. I know nothing of those setups.