I would use a single bevel groove weld where the corners meet. This will be a partial penetration weld. Compute the groove depth you want based on the required weld size and then determine your weld spacing. On the other end, where the toes of the angles meet, I would use a fillet weld and have the toe of one angle ground down to accommodate this weld. Using this approach you will only need one angle prepared for the welding, apart from grinding the surface of the second angle just prior to welding. Good luck.