I'd avoid the rollers given the weight of the carolina. I have some 58lb fiberglass kayaks and even with the rollers attached as hard as I could on the round bars, the rollers would twist around the bar under the weight of the boats.
See here:
http://www.yakima.com/Product.aspx?id=48
Download the instructions PDF and you can see how the weight of the boat on the rollers will really be directed straight down on
one side of the round bars. Being round, if the boats are heavy or you tend to tie down pretty tight on the ends, you might experience this problems.
Yakima suggested I tighten them more. I did and eventually tightened them down so much it literally crushed the lining on the bar. They send me a new bar and a free set of Mako saddles to use in place of the rollers I bought. Now I only use saddles on each end. The way they mount the weight is centered over the round bars and they won't twist around it. Plus, it seems you can get the boat more firmly tied down on the saddles than on the rollers.
I've found that if you don't want to just lift the boat directly onto the saddles, you can slide it along the saddles just fine. Of course, I don't car top on anything taller than my grand prix. So I can't vouch for how hard it would be for you to do it this way onan H3...certainly easier than an H2.
BTW, don't tie a plastic boat at the ends too tight. I've seen far too many people cartopping their plastic kayaks with the ends bent down (i.e. bending the hull) in warmer weather. This might be okey on a quicky run in town, but any longer will damage the boat.