Those fittings are SAE, not metric - I think one is 7/8 and the othe 11/16 but my memory could be off. I've had good results with crow's foot wrenches and also by using a cutoff wheel to make a very short-handled wrench. If these fittings have never been apart they can really be stuck and you can do serious damage to the copper pipe going into the evaporator. Use MAP gas torch (like a yellow butane torch) to apply heat (have a fire extinguisher handy too) and also use striking blows with a hammer on your wrench, rather than steady torque, to break the fittings loose. Steady torque will twist your pipes rather than breaking loose the fittings