The way I do it is add.100 to each lam you want.
.035 for sanding saw marks out and .065 for the bandsaw cut
So .130 x 4 = .520 , but I like to have plenty in case you run into a booger inside the blank....
So I would go minimum of 5/8" thick.
One other tip which I'm sure you know, is make the pcs a little extra width when gluing the 2 woods together, so you can straighten if they come out with a little bow or sumpin! :cool: