This is a very useful guide. My first few attempts are not great likenesses, but I think I'm starting to close in on some promising results.
I spend a lot of time realigning to OnTopReplica images as I want to view things from various angles, so I'm planning on trying out some fixed camera cycling to iterate through them much faster.
Also, to save others some time, if you get horrible results from Facegen and think you can just doctor up the input images, the results will likely be even worse. Facegen seems to get really confused by edited input images, such as even some minor shadow lightening, etc., such as I did to try and get it to stop creating a third nostril and skewing the entire face due to some darker shadows under that nostril in the input image.