I cut a piece of Hepa cloth disposable bag material from a Simplicity type F HEPA bag, into a square. I place this square over the pre-motor hepa filter and I use the blue paper Platinum Bags. While they do leak some fine dust, it's caught on the HEPA bag material and my pre-motor filter is spotless. Lots easier than making a Hepa bag with a glue gun.
Interestingly, my Platinum Edition's motor stops when the full bag light comes on. I have the very early version with the first power nozzle cover. Here at the Museum, they sent me (free) a second one (to display) with the "new" power nozzle hood. Haven't got any dirt into it yet, but I'm assuming it shuts off when the full bag light comes on too. One day I'll have to actually vacuum dirt into it to see. Right now, it's a "rug virgin".