Signatures are a lousy form of validation for voting in my opinion:

I'm a Washington state resident and because I sign a lot of checks I have two forms of my signature: My 'fancy' signature that has every letter of my name and my check signing signature that is a scrawl of simple squiggles.

I used my fancy signature for voter registration and accidentally used my squiggle signature for my fist mail in ballot and did't get any kickback. I've used it for six years and King County elections still has never questioned it.