Well, I was finally able to do a bit of work on my multiplane today. That probably had something to do with the fact it was 70 degrees outside and sunny. Thus that meant it was very comfortable in the garage today, where I had to do the sawing.
To get the final positioning of the two main "planks" I had to do some simple mathematics. Basically done by doing some measurements of the wing frame and eyeing it. Since there are no dimensions out there of the positioning of the two main "planks." But the overall result I believe was suprisingly not that bad. (Had to tape down the frame so I wouldn't lose the positioning I wanted.)
To cut the support truss for the main frame, you'll need a miter box and a saw(almost any saw should suffice.) For the support "planks" I used the same wood and same size, 0.20 X 0.30. (In order to save time I cut this piece at the same time I was cutting the wood that I would later use for the two main "planks".)
To make sure I didn't get too much splintering of the edges or cracking, I slightly notched all the sides of the wood I'd be cutting with a razor blade.
Here's all the support "planks" for the main frame cut to about the needed size. (Yeah, I know it looks more like a ship then a plane currently.) I made sure my cuts were bigger then I needed, since I still need to sand down the edges to have a slight curve, in order to fit perfectly in between the two main "planks."
Now I have to get out the sanding paper/sponges and start the task of sanding. I have an electric sander(might try it on these small pieces, but only if I feel it's necessary to speed things up.)