I have been using KRX's method as well ever since he turned me on to using a USB stick instead of DVD's. The USB was a whole lot faster and then when Amazon put some 8GB SSD's on sale I snagged me a set of 4 for $20 and that really speeded things up and now I can do quite a few more builds in a day than before. Thanks again KRX!!!
I also keep everything I don't want wiped out every time I do a new install on Windows on a separate partition so it's easy to get to. All my drivers and favorite software like Firefox, music, my space strategy game, and YES of course WinReducer and ISO's, lives on a totally separate partition and so that in itself certainly makes life so much easier and faster.
I just remembered too that since I have been involved with the Win Reducer project that I replaced my old hard drives in both my computers with Solid State Drives and speed difference is incredible. So when you couple the use of SSD drives with SD cards and USB sticks everything speeds up the whole building process. When I first started out doing builds in was a very long tedious process and like I said earlier, I can now knock out quite a few builds in a day. I already did 15 today (almost one an hour) and started each build out with a fresh ISO each time.
I have also learned that the less drivers needed the better. Removing as many drivers as you can and also the less drivers you need for a build really makes a huge difference in not only the size of your final build but the install goes much quicker. I noticed if I did not add any driver files whatsoever to a build that after the install there were only 3 devices that needed drivers and so those are the only ones I have included in the build. This whole process is a huge learning experience and learning from each other makes it all the more enjoyable. We all have each other to thank for making the whole project a big success and a lot of fun.