I bought my taper board from Kenny, it starts out about 3/8 and tapers .002 per inch, Kenny will custom grind one for ya if ya wish. I just lay may lam against the taper board and push them through, then flip both and run em through again to make sure of square. I just work one side of the lam until I have a good grind and all of the saw marks off, then I grind the opposite side down to my desired thickness.
I do push on the one side until the lam is through far enough to pull the rest of the way.