I do a lot of crankbait trolling for crappie from my kayak. I like 6'6" light or medium-light action rods. Two spinning rods have Shimano Stradic 1000 reels and two casting rods have Daiwa ADP17LCB line counter bait casting reels. The Spinning reels have superior drag compared to the casting reels, but both work.
I found that rods longer than 6'6" it was difficult to untangle line or a lure wrapped around the rod tip. Longer rood gives good leverage on fish and wide coverage when I'm searching or trying to stay on a school.
Jim