I've never used the kits. First of all, they rarely include the engine brackets and that's usually the biggest problem if you're plumbing into an odd-ball engine. If your engine has a compressor mount already, they might do the job!
I like to gather my parts from local suppliers (check the yellow pages) Most carry all the components and are more than willing to work with a hobbist. Even to the point where I bought all the components to fit, hoses too, and then they crimped all the connections when I got everything fitted to meet my needs. Being able to run the lines and mount the components where I wanted them was a serious consideration. Evacuation and charging cost me $35.00 from a local A/C shop. My systems averaged less than $700.
It takes time to gather and figure out how to make everything work properly, but isn't that what building these ole trucks is all about?
You said it "sometimes the slow way is the right way".
Hope this helps.
