You will find minor differences between the lounges, not enough to justify jumping around MUC in my view. You can stay non Schengen but I can't see the benefit of that and the lounge agent will probably suggest you get nearer the departure area. I would sugget you clear Schengen and then go to the Senator lounge nearest your departure gate. This may well be Senator G28 in the main building, clearly signposted, it's a few blocks back from the gate G28 itself.