I'm having someone make me a custom rod an he wants to know if I want a split rear grip. I wanted to know if anyone has fished with this type of grip and what do you think of it. Don't think it would bother me because the only time I put my hand on the lower part of the rod it to cast. The rest of the time I palm the reel. So if anyone has any info that would be great. Thank you.

There are a couple schools of thought on it...  technically it's lighter but affects balance in the wrong direction...  (only a tiny bit)  If you are using burl cork then I would suggest it as burl is over 2 times as dense and heavy as regular cork.  It also gives the builder the opportunity to shape the 2 grips differently for function and comfort instead of a long straight grip (or long wavy grip).  And it will cause your rear hand to be placed in the same spot more often and likely increase your casting accuracy as well.

They look cool- at least to me.  I haven't had anyone use one of my rods that didn't comment on liking the split grip better than a straight one.

Since it's a custom, why not get a unique look?  I'd say go for it, I can't imagine that you won't like it.