It looks like the front of your guard is open. Doesn't that allow some dust to be thrown forwards? or do you have strong extraction connected?
My guard works even if the hose is not connected to extraction. The blade creates an air flow that carries dust down the hose.
I don't have a problem with it pushing backwards when the work piece hits the front as it is bayonet fitted to my home made riving knife. I do lose some depth of cut but rarely find that a problem.
If you do change the front angle you could try filling in the front at the same time - assuming it is open as it looks in the picture.