Tony
After my RO a reading of 2. I had a bad membrane and had similar results to what you have going on. Luckily I changed it and things have been running smooth. So you must have something wrong for sure. So you'll have to fix that and I don't think it is related to your float valve set up. I believe it is best for your RO to operate a few times every day, the more the better for it. Is that not what you have happening? I believe the worst thing for RO/DI is long periods of no flow like a day or two.
For info sake I have my RO/DI plumbed into a 5 Gal. pale on a float. In the pale are my two top off pumps. One pump is controlled by a Tsunami see link, it supplies my predator tank.
http://www.mops.ca/cgi-bin/SoftCart....html?E+scstore
It works fine and after three years has not failed (knocking on wood now). It did not have the exact control I was looking for on my reef and went the Tunze top off system on my reef. I love that little toy, pricey yes but does a great job. I'd guess it turns on dozens of times over a 24 hour period keeping the flow through RO/DI going on and off.
Also plumbed out of the 5gal I have a line that flows down to a 33gal rubbermaid to store water change water. There is regular float in that container. And then... from that container I pump manually into other rubermaids to mix salt in.
The end sorry that was so long.
Dave