I have found Dana @ Probuilt to be a good source of reference. While I have not bought anything from him yet, he is still willing to help me wade through my first 700 build. The 700 is very similar to your 4L60E-same internals, just different valve body, wiring harness, placement of bolts on valve body, length of some bolts, and several other pieces that the 700 does not have. Anyway, I'd bet money that if you purchased your parts from any of the known vendors out there-like the ones that support this site, they would be more than willing to assist you with any problems you have with your build along the way.
I can recommend that you start with the ATSG manual for your year of transmission. They are very straightforward for doing a stock rebuild. If you plan on venturing off the stock path, they are basically useless though. For performance mods, you will have to partner with your parts supplier to ask for the inside scoop, or buy one of the complete performance kits that will come with all of the upgrades included.
I think the reason it is so hard to get good information from trans builders on the web is that most of them work in excess of 10 hours (or more) a day, and I don't think that at the end of a long day they want to sit down on a computer and type out what it has taken them years & years, & years, to learn for FREE. Not saying they don't want to help because most really do, but would you really want to explain to a stranger over the internet how to do your job at the end of a 12 hour day knowing they have no prior experience, don't have the right tools, and lack the "feel" that only comes with experience? That would be like guiding someone through open heart surgery that has never operated on a human before.. Just far too difficult. So while for the amateur, like myself, it can be frustrating that you can't get the answers that you need in the instant that you need it-that's just the way it is. Read all you can. Buy all of the books that you can get your hands on. Look up the different companies shift kits and search for their instructions on-line. A lot of these kits are very detailed in & have good pictures so that you can see the name of parts, and how it all fits together.
And last, don't expect to be able to sit down and do this in a couple hours. As I have learned, it has taken me over 3 weeks now to get mine back together. I keep having to stop and buy parts that when I tore it down looked good, but now that everything is cleaned, you can see the wear, cracks, fatique spots, clearances are off, etc; That's another thing, try and get your clearances as close to spec as possible. If you are not close, don't just think that it will work as it may, or it may not, and if not you will be doing it over again real soon. There are backing plates, apply plates, steels, and frictions of different thicknesses to get each of the stacks to exactly where they need to be.
I'd say buy a used core transmission that will work in your vehicle and start working on rebuilding that core while you keep your daily driver up and running. That way, you can take all the time you need to get your rebuild done right, and then it should only take a day to swap the rebuilt unit into your vehicle. If you have problems with your rebuild, you can always just swap the old unit back in and start again on figuring out what you did wrong.