dd,

I didn't use a specific ratio, but I did make it pretty thin for just the reason you mentioned. I wanted the mixture to saturate the threads and not just cover them. You could apply the silicone directly from the tube and leave a thicker coating, but I don't think you will get good penetraton of the thread and I believe it is suseptible to rubbing off. I stretched the seams pretty good, trying to open the needle holes as much as possible before applying the silicone mixture and let it dry for a couple of days. I used Coleman fuel because it was handy and evaporates quite quickly, but any number of solvents will do the job.   

Pat