frankgh,
I agree with what you're doing 100%. I would add that the chlorine level you want to maintain, is dependant on ensuring your pool is clean of algae. For some, it may require higher than 1.5 ppm. For some, it may be as low as 0.5 (indoor, covered, and lightly used pools).
There really is a benefit to having the ozone injected before the cell and that is that more contaminants will be treated by the ozone, prior to the cell. Again, this allows you to reduce the output of the cell to maintain the same amount of chlorine in the pool. Strannik is right in that even if you plumb the ozone after the cell, it will still ozonate the water, but not as efficiently as before. `
As an example, the Canadian system, Ultrapure, is primarily installed in the pump drain plug to ensure the longest "Contact Time" possible in a standard residential plumbing scheme. Most commercial ozone systems have a large volume "mixing chamber" to provide the longer contact time.
AutoPilot just came out with the Co-Pilot series, which incorporates either the Cubby unit or Digital unit with the ozone venturi built in with the Manifold, prior to the cell.
http://www.autopilot.com/index.php?cPat ... 66ac18ce1e
Richard, I would disagree with you on your statement that ozone will kill algae. Ozone has very little ability to kill algae, especially since it is released into the atmosphere quickly after returning to the pool. There is virtually no ozone that is kept in the pool water as a measurable lasting residual.