I like the idea of using tissue. Didn't think of that. Sure way to know if it dripped while you were away.
I also agree that once the system has heated up, some of the compression fittings may be able to be tightened more. That has happened to me more than once.
I did my leak testing with the system on it's lid so that if it did leak, it would just leak onto the rad.
In my short experience, a properly installed compression fitting at least gives a feeling of a more solid connection, and they look better than barbs IMHO.
As GJ says above, making sure that the tube is properly installed on the fitting before tightening the collar is important. If the collar won't slide down or catch the threads of the base you may not have the tube seated well.
Edited by pgdeaner - 9/6/12 at 9:49am