This is the way I'd do it if the project was mine.

Barrel length and shape.... 24" Round.

Barrel contour.... Heavy at chamber section, heavy taper down toward forward tip of fore-end, tapering from there down to light muzzle with a 100 to 120 thou wall thickness. Sling eye mounted on barrel.

Iron sights.... front- uncovered bead, rear- single standing shallow V with platinum line.

Other suggestions.... While total weight and overall balance are important, weight distribution and fit are more important in my book.

10 pounds is not too much to carry IMO.
I sometimes hunt all day in steep country carrying a 10 pound double.

Best of luck, and please keep us informed on your progress.