First, figure the leaves needed to cover a three inch, gold, length of the molding, (overlaps), multiply by four, then multiply by the number of feet.
A 30 + 40, = 70, 3.5 inches wide, + 7, divided by 6 = 12.83 = 13 feet. If it takes five leaves to cover one 3 inch length, (overlaps), because of the depth of the molding, and 3D ornament or carving, multiply by 4 ( the no. of leaves in a foot), then the no. of leaves to cover the whole molding. 13 x 4 = 52 x 5 = 260. A little over estimation is good, though I have done some frames where my estimating was right to the leaf, leaving me just a few for some sort of insurance. With gold, I usually figure my needs, and seldom with metal, as there is usually enough on hand, and the economics are different. Framers all round up at some point; for me it is a half foot.
Happy gilding! I tend to water gild gold in the evening, after dinner, after a drink or so, as I am calmer and less bouncy. Machining and carving are usually done in the day; toning is a day time, frenetic dance. I can carve in the evening, but running machines is a daytime, sober, scary activity, and I have 9 and 7/8ths fingers to show for it. You can screw up at any time, so pay attention, and listen; if it doesn't "feel" right, don't, relax, look at it critically. Fingers are ... good!
I've been doing proposals for 19th. c. reproduction frames, thus the picture.