Seat fastener

Yep M6 and 1 1/4 inches is long enough for me and I switched mine to stainless, as I am switching all fasteners to stainless when the occasion arises to remove one. I would like to make the seat bolt a thumbscrew, and will should I find one which suits my fancy.
 
Why we are touching the subject of fasteners anyone know of a company that sells black anodized?
Would love to change all the bolts out to black. If not, then stainless.
 
Thank you all. I added the sizes to the first post to make it easier to find when folks search.
 

I have the Corbin seat and it mounts only with 1 rear bolt