/sci/ - Science & Math

So I have a project where we have to construct a truss out of either sitka spruce or basswood capable of holding 1000 lbs. (Although more is obviously better, 1000 is just the ideal) I'm working with a range of around 22 x 7 inches.

I've been looking at bridges for a while, and it seems like the best options are the pratt truss and a K-Truss design. Howe and Warren don't seem to be any more efficient.

Given the constraints, should I model it after one of these types of bridges? It seems that the K-Truss, although might be extremely difficult to build, would hold a lot of weight. However, at a scale like this, can it be as efficient as a pratt design? There is a factor of materials, weight, and thus efficiency I want to account for as well.