I find using maguires clay bar to last the longest but where most people use some type of spray wax to keep the area wet is where I differ.
I use simply green where it will offer a two part benifit.
1. This is a cleaning product that isn't harmful to the surface and will help clean your paint.
2. There is no lubicant that will out do keeping the suface lubricated and as above mentioned as well.
3. This will help cross contaminating waxes where as when you use a spray wax the first thing you should do is take off the excess before applying the next step. One of the biggest problems people run into is having swirls and that is usaly from crossing waxes from using the same pad to apply or removal or leaving the spray wax on and going to the next step or simply a build up.
4.When you use simply for clay baring the only thing is rinsing afterwards. The need for using a high end car wash at this point is not only a moot point but adding a form of wax that is intended for washing in between rounds of full detail just shammy the car off and begin what the people before have said.
I have used meguires and adams products and love them both.
This is a pic of my 93 sporting the original ford paint that at the time of the pic the paint was 11 years old and you could still dive into it not to metion it is a light colored paint with iluminesent lighting.