Sorry for the confusion. Basically, replacing the bend with a simple slot simplifies things greatly. I think that the slot is enough because the card is supported from all sides; screws in the back may be redundant because the front panel will prevent back and forth movement.
Ohh by front and back panels I thought you meant the motherboard plate and side panel mounting plates, but you meant literally the front and back, because you kind of "fasten" the entire case to the graphics card. This case keeps stumping me, the innovative design defies all conventional thinking. Yeah, you don't need a flap with a screw if the card is perfectly cradled, unless someone wanted to give themselves more wiggle room, so they could take the card in and out without disassembling the case -- just curious, how short would a card have to be to take it out w/o disassembly with the case extended to maximum length?