I think your best guess would work well. Just look at the picture of the baffle on the website. You can hold a ruler up to your computer monitor and measure the height of the baffle relative to that of the cabinet. This will give you the correct proportions which you can then blow up to full size using simple mathematics. I don't think speaker building is rocket science. In fact, slight irregularities actually help break up standing waves better. The baffle in my Mock 212B is actually set at an angle and the holes cut are not entirely evenly spaced. when we install the speakers I am planning on staggering them slightly as well.