Cam Cleat Fairleads?

The cam cleats on the Nacra I jsut bought are toast. So, I bought 3 new ones (Harken 150s). Now I wanted to put some sort of fairlead on them. The low plastic ones seem like they are too small for a 3/8" line. Should I just get the stainless loops or get a nice roller fairleads?

Any advice is awesome, thanks.

The only way to answer your question is to understand what purpose the cam cleats are serving. How much load will the cleat and fairlead be bearing? How often will you be adjusting? Where are the cleats located?
We have similar cleats on the Miracle 20 for our mast rotation adjusting line and due to its location, had a tendency to leave bruises on us crew. A simple fix was to screw in a piece of line without the core as the fairlead. Very low profile and much easier on the crew.