Sadly when Mike Musick retired from the National Archives their REAL Civil War expert was no longer there. They have not groomed anyone to repalce him either and this was at least ten years ago now.
They do have these microfilm rools as I have worked with them. You are just going to have to go there and do the work yourself as they will not do much more than cursory looks in the Complied Service Records and even then if you want a full file you will have to do that yourself as well.
I speak from experience and I have researched there many years. It is a wonderful place to go.
Greg Biggs