To do an arched gluelam you want to have a very stout jig for clamping. For the base I would use 3-4 layers of 3/4 ply to mount your clamping points to. This is where you can do all of your lay out. It is helpful to have a outside and inside layout. Make this layout pre-springback (I will get to this later). It is nice to have a full scale form, a inside and outside form... but you can use points about every foot on the outside of your curve. Use a hydraulic jack to do the moving, and then use acme thread to hold the beam in place while you reset the jack. Place the jack in the center, and the threaded rod every foot or two along the radius. The acme thread goes through a nut that is welded to some angle iron that is bolted to your jig. Then reinforce it all with all of the clamps in your shop.
No matter what your glue is or your laminate thickness there will always be some springback. I like using a urea formaldehyde glue. It provides a little flexibility without failure and overall is a good glue for this application. There is a formula for choosing you lamination thicknesses based on radius for hardwoods and softwoods. I prefer to always go a little thinner on my laminate thicknesses... makes it easier to bend, and less springback.
Depending on the grade of your wood you may even want to go thinner. The more knots you have the more the greater chance you have of the wood breaking while bending. Give me some time looking through my library and I might find the formula, but it never hurts to go thinner. You can also use a less expensive wood as a core with your finish wood on the surface... the top and bottom layer could be oak, and the remaining layers could be a pine core with 2 inches of oak glued on either side. It looks like a oak curve but with a pine core. It also helps to throw some fasteners in from the top. Wurth makes a good screw for this, the product name is the ASSY VG Plus. It is a fully threaded screw with a thick shank to hold all the laminations together. This for me is just a nice insurance policy to the glue. The best advice for layout when framing with shop made curves is to scribe them into your frame... if they are a little bit off your radius the scribing will take that into account. Hope this helps you get started...
