I had contacted Flyboys/Pivotcase after suspecting that the hand strap would interfere with the Leg Strap. After being assured in a response that all Pivotcase products will work without interference I bought the Hand Strap.
You cannot mount the A35A onto the Leg Strap with the Hand Strap installed. Worse, it will pull the Hand Strap out of the A35A, then, you have to remove the iPad in order to reinstall the hand strap.
If you regularly go from Hand Strap to Knee Strap you will be required to remove the iPad once to remove the Hand Strap from it, and do so again to reinstall it. I can't imagine repeating this cycle often won't lead to wear and loose fitting of the A35A to the iPad over time.
If the Hand Strap had a quick-release buckle on one side it could be unsnapped to mount the A35A onto the Leg Strap, and still be easy to reconnect for handheld use.
If you make this change, please send me an upgraded version.