Which rod would you use for fishing 1/4, 3/16 jigs? Medium or medium heavy? Is it a personal preference or is one better than the other. Light cover and open water only. I was looking at the 6'10" medium for this application. Feedback would helpful thanks. I wanted to keep the rod over 6'6" and under 7'. All my rods are Shimano crucials.

Personally would go with a MH, a little extra power for hooksets. Take a look at the Dobyns rods.

For that light of jig, Id go with medium.

<1/2 oz I usually go with M/F spinning

I agree...I've experimented quite a bit the past two years with various jig rods.  I've settled on a 7' M/XF rod (All Star) for jigs less than 1/2oz.

I fish my light jigs with a 7 foot Medium Extra-Fast. It's a Dobyns 702C. It says it's a Fast on the website but it's more of a XF.