He's known as a great signer and since he is, he's very affordable. My amateur answer is that yours looks fine. Here's one I just got in a larger collection from someone who collected in the 70s. Although they may not match perfectly, most people's signatures change with time and they show many more similarities than differences.
I added the yellow box to show how I might frame it with something else. I've always thought of him as the "Bob Feller" of celebrity signers. Great guy who signs (signed) for everyone.
PS: A lot of common sigs aren't worth sending in to PSA/DNA or JSA if you feel good to begin with. The cost would be more than the auto. IMHO