Icon308-- I'm not an expert on anything to do with optics, but I'll throw a couple of things out for your consideration. The "wallow room" they're talking about is a bigger eye box with the larger exit pupil. In other words, the positioning of your eye behind the scope is not so critical to get a good view. That may or may not be a big issue for you.
The first scope I bought was a 2.5-10x56 Accupoint. I was planning to do a lot of hunting at night and went through the same process you're going through and read the same things you're reading. The German night hunting thing is different than what we do here. The hunt at night but are not allowed to use lights. Dusk hunting and night hunting with lights are much different. The big Accupoint worked great, but it's big and heavy. I switched to a 3-9x40 Accupoint, which is much smaller and lighter, and had no discernible functional decrease in what it offered me.
If you don't mind the extra size and weight, a 50mm obj certainly isn't going to cause a problem for you, and it might help in some cases. I didn't see any difference between what the 40mm and 56mm obj offered me from dusk into full night (using a red light at night) at distances from 25-200 yards.