I would recommend building it and getting used to it first, then baffling it to suit the eyepieces you most frequently use. The thing with bino's is that you will see a lot more detail for pretty much any given magnification, so you will spend more of your time with longer FL eyepieces. In my experience, the increase in detail perception follows the rule of the square root of two. ie) If a 12mm eyepiece is your favorite eyepiece in a monocular telescope, then you will see the same amount of detail in the binoculars with 17mm eyepieces. (all else being equal)
I found that at F/5, ninety five percent of the time the 17mm eyepieces gave the best views, only swapping to 12mm for viewing the planets.
Once you have narrowed down the range of magnifications you are likely to employ, this will give you an idea of the size of baffle required under the base of the focuser. I would then experiment with different sized baffles at this position to optimize over all contrast. This is the single most important baffle in the entire OTA. The best position for this baffle will be approximately 23mm off the side wall off the tube (102mm away from the centre of the secondary mirror)
For the rest of them, there is only one which needs to have a sharp edge, that being the one that defines the aperture stop at the top of each tube. Make it a couple of mm larger than the clear aperture of the primaries, and the rest of them can be cut from 2mm ply (or kydex) using a router and radius bar, and make the diameter of hole a couple of mm larger than the aperture stop. This way, you can cut a whole stack of them at once.
Here's one of my tops made with 2mm ply, cut using a radius bar and router.
http://i858.photobucket.com/albums/a...lne/20top1.jpg
regards,
c