It is fairly intuitive, the inner comes apart easier than the outer. It's messy, really messy though... I've done a bunch lately and I think it's fair to say that if you mark the index between the parts, take them apart, clean them and re-assemble in the same index with new grease and boots around 150K, they won't fail from dry grease at the mid 200K mark. It is fairly labor intensive though...
I recently used a GKN replacement inner, ~$100 and seemed quite nice, there's a Mattelli inner out there for a little less $, I have no experience with them but sounds like it might be worth a try.