Hey my recent amazing hef was similar, 6lb alex. wheat, 4oz caramunich I, 0.5oz fuggle5% for 60min. I did the late addition as well, to increase hop useage and keep color light. A full boil will further help keep the color light, and further hop utilization. Either of those hops will be fine, hop character is minimal with german hefs. I believe the caramunich added a subtle mouthfeel, which I was really hoping for. I did ferment at lower temps though(65), as per Jamil's recommendation in Brewing Classic Styles. The yeast charecter is amazing, though I think you're right about bananas and higher temps. also, used WL german hef IV, plus WL belgian wit(only one germ. hef vial). The outcome? So good. it tastes like Brooklyner Weisse. Good luck.