HD Get-a-Grip & Avon are my two recommendations. Don't fall for the fancy names w/bling who up-charge to stamp their logo on end-caps...you're paying for them to advertise and they're crap.
I have nostalgics on my heritage and get a grips on the dyna. Both are comfortable and look great. I was concerned about them being too fat ( little hands) but they are perfect.
Kuryakyn ISO with throttle boss. I can say I have never had a problem with my hands cramping or any other issue. While i have serious reservations about Kuryakyn parts, the grips are really nice.
I have this setup on my Heritage as well and am very impressed with the comfort.