I'm trying to learn all I can on my own, having looked around last night for a while I ended up stumped. I seem to have several different t's though. And the F i think looks like an old F, he's not young in this picture.
I almost wrote, "I think this is secretarial", but changed my mind. There is a great page with a study of his signatures, but after a while they all blend together:-)
I found something similar for Reagan, after reading that I felt like I knew what at least to preliminarily look for. The text explained it I thought better than the pictures did. I think I have one Van Damm and two real.