Hours? You mean weeks maybe! There was some thrashed material to start with, just to get it to a decent starting point. And trying to design the chassis and coilover rear suspension to be repeatable and usable on different frames in different configurations is a pain.
I sometimes wonder why I chopped up a perfectly good K5 that was a better all around vehicle than what I have now, but every little step seemed like the right thing at the time. And sticking with one vehicle and building it smart lets you spread the labor and $ cost over time which makes it easier. I'm kind of proud of my 14FF that's been in my K5 since 1995, for example. And, what do you do when the sheet metal is thrashed? Replace it? I don't think so, unless you retire the truck and after a while, it gets to where you couldn't get fresh panels to bolt on and line up anyway. I just wish I'd reached a point where I could start at the frame like Fox, his chassis is about 8" narrower than mine since wally's based off the in-cab cage that was never designed for being a tube chassis. Everytime I've thought about starting over with the cage, we look at it and see too much work that would have to be re-done and leave it alone. And it's definitely DONE now.
Coil front or rear? I did the front because I wanted better steering and wheel travel than I could get with leaves up front. The leaves with traction bars worked OK in the rear with the full body so I left it that way. It almost comes down to how fast you want to drive. If you're crawling, you should probably link the rear 1st for departure angle, clearance underneath and wrap control.
For higher speed, you'll probably want to link the front to get more usable wheel travel with better steering. A set of long rear leaves can easily give 15"+ wheel travel and with a traction bar will control the torque well enough. With the coilovers up front, I got 15-16" of vertical with good steering and control. That kind of travel in the front with leaves would be a nightmare to drive unless I was to unleash some of the complicated makes-sense-only-in-a-race-vehicle stuff I've dreamed up.