Hi Irene.
I'm using 1/2" wood and around 1.25 degrees. I use a #3FDUR blade. The angle seems to vary with the different types of wood. I try to get the angle so the pieces stop just before they are flush but I struggle with being consistent. Most of the wood I'm using was given to me and is rough cut and up to 1 1/4" so getting it ready to cut has been a big part of the work. In case you're interested I'll try to explain how I do the Capt. America shields. You want to put the color wood that you want the star to be on top. I cut out the inner circle with the star still in it first, clockwise. I cut the star out by cutting the 5 sections of the inner circle around the star individually counter clockwise. I label them 1-5 before I cut out! Then the first inner stipe or ring is cut counter clockwise. Next I cut the middle ring clockwise, and lastly cut around the outside with the blade square to the table. Gluing it all up is a hot mess for me. *After breaking an outer ring while putting one together I've started putting a hose clamp around the outside fairly snug before "persuading" all the pieces to tighten up. I put a block of wood on top and tap/"bang" it with a hammer. Then after about an hour or two of drying time, I sand it flush with my belt sander, round over the edge, fill where necessary, and finish sanding. If anyone is still reading at this point, sorry if that's a terrible job of explaining and I'm sure others may know a better, easier method!