A lot of it has to do with your design - i.e. how much reflex/deflex, and riser length. Custom bowyers need to build many bows with a particular design to really nail down exactly what stack thickness (number and thickness of lams) needed to hit a certain draw weight. Lots of trial and error.
Since you're brand new to this, your best bet would be to check out Bingham's Projects. They have everything you need to get started (instrucional materials, hardware for a form, glass, laminations, etc.) and you can order one of their "kits" which will give you the right glass and laminations to hit a desired draw weight if you stick close to their design. Many bowyers started out with Bingham's kits and it is a good way to make sure you end up with a shootable bow for your first one.
Kenny McKenzie who is a sponsor here (Kenny's Custom Archery) also makes some awesome laminations and could also give you some advice on lamination thickness for a r/d design.
I build straight limbed "Hill style" bows and have figured out my thicknesses to hit 55 - 60#, but haven't tried a r/d yet. I'm planning on building one after hunting season is over. So it will be some more trial and error for me too.