A sixteen sided figure is a hexadecagon. The internal angles are 157.5°. So the miter angle to be cut on the ends of the horizontal struts is 180 - 157.5/2 = 11.25°. This is the same angle which must be double beveled on the faces of the vertical struts. Which will be laid on the 'flats' cut away from the ribs. Both to reinforce the ribs and provide a substantial bed for the flat, trapezoid, 4mm plywood sheathing panels.
I have bought some 43x43mm timber for some experimental struts to make up a single dome segment. However, the continuing bad weather has stopped most work on the build. I need to be outside to have enough room to cut the 9mm plywood arcs for the dome from 5' x 5' sheets. It is not the matter of a few moments to tidy everything up between sudden cloudbursts. September 2017 in Denmark is heading for an all time rainfall record. There was more rain on one particular day than the average for the whole of a normal September. The weather has constantly flip-flopped between sunny and cloudbursts. The regular gales don't help.
Thanks to Paul Robinson's Geo-Dome trapezium dome calculator
I can find the weight of the struts.
More information here:
By a happy/unhappy coincidence 43x43mm softwood [pine] weighs close to 1kg per meter, or roughly 2.2 lbs/ per m or 39.4".
Vertical struts = 16 x 4 = 64 x 64cm = 41m
Horizontal struts = 16 x 64 cm = 10.2 m
16 x 59 " = 9.5
16 x 45 " = 7.2
16 x 24 " = 4
Total length of struts = 71m
Weight = 71kg or about 156lbs. Eek?
To which must be added the weight of the 4mm plywood sheathing, of course.