Sorta, my pressure flaking plate form starts when i am doin percushion , lemme just got through all the steps i use.
1st i edge the rock, than i thin out the thick parts and once i get a consistant bi-face I'll set a platform up down one side of the bi-face so to take flacks off side 1 and i also set up a platform to remove flacks off side 2. once th plate forms are set up on both sides of the bi-face i than remove the flacks from side 1 and than side 2. and i repeat this proses until i have a thin preform and i use the same proses when pressure flaking.
I've learned that when pattern flaking its best to have a cross section that is more convex , but not to convex.