You're grip's gonna suffer on Sheiko unless you do things to specifically help it. At least's that is my experience.
My grip actually dropped off the frist time I ran sheiko and I had to do alot of work to get it back.
Once it did come back I pulled PR after PR tho.
Don't give up on mixed grip just yet, there's a very good reason all the worlds best deadlifters use it. (expections like Brad G. obviously)