these are just my guesswork, but here goes.

barrel lenght 28-30"

that would be around 10 pounds(im going from my 20/577 now)

proberly henry rifling.

proberly express sights.

please remember that i havent seen it yet, but i know the action quite well, it has a size that easy can accomendate a 10 bore(BIG actions)

remember that alex henry were the late black powder era roy weatherby. for that time he were really pushing it with his other loads, but we will know tommorow for sure

i will see if i can snap a picture of the one i have here next to a 12/70, so you can see the size of the action.

cheers

peter