Of course there might also be a weight loss to be found in plastic lenses (horrors!). I am viewing this screen very clearly through polycarbonate right now.
As for the Zeiss I am only getting a 2 ounce reduction from my Celestron 8x42 pair if I go that way. For the 2 ounces I'll take the aperture gain. I lose 6.5 ounces by going with the BNISE units. As far as comparisons go I do have the Celestrons for comparison. I don't doubt that the Zeiss is better than the BNISE but if I can be in the ballpark and not have to worry about losing them on a trip that would be a win for me. In any case the experiment will be fun. If they are good I will have found a diamond in the rough. If they are garbage we will all know, and I will try something else. This is entertainment not life and death and I am enjoying the journey.
I would love to see the results of your weight tests Ant1. I hope manufacturers watch these forums and consider new design ideas. There are a lot of great products out there but there is always room for improvement.