Bam Bam, if you "round off" the little platforms in the notch, here`s a trick that works..............sometimes. Make a chisel point out of a deer antler tine about 4 inches long. Since your sandstone abrader won`t fit in that narrow notch, use a flint flake to grind the platform. Lay the point on a leather pad and lightly place you foot on it. Place the chisel point tine on the platform and get it at the correct angle. Use your hammerstone or antler billet and tap the tine to remove the flake. Turn the point over, grind the platform and go as deep as you dare. This also answers your question on indirect percussion.
Be careful not to let the tine flex in the notch. Bad things can happen!! Here`s a prime example!
Never forget--IT`S JUST A ROCK!!!
thanks nick. i will try it and post my defeats. if is like anything else in knapping it wont be easy to master. i got me some georgia jasper i am saving for when i get real confident.