If you shop for some 32mm binocs it is not only the weight but also the size that makes them handy. I've been hunting with an old pair of Zeiss ClassiC 8x32 for example, and they are small enough I can stuff them into the pocket of my parka. So I suggest paying close attention to size, some 8x32 are almost as large as 8x42s.
In regards to the loss of time viewing dusk and dawn, in MHO you can see well enough to shoot with a danged ole Leupold scope within the legal time frame of most situations from 30 minutes before or after sunset. So, yes you can still see during legal light with a high end 8x32 binoc. Although a 42mm will be a little brighter. Also, I've learned that I used to think of legal light as being darker than it really is.
This past season I was in Kansas hunting with an outfitter that had some aps on his smartphone that could forecast the direction of wind, and the exact time of sunset locally. When hunting out of state I pay extremely close attention to legal light because I believe that local game wardens drink coffee with their local hunting buds who complain about out of state hunters, and they more than likely would not pass a chance to charge an out of stater with a violation for even ten minutes of light. Anyway I noticed that stopping at legal light I didn't really need a flash light for part of my hike back to the pick up point
Happy Hunting
