Hi JK,
I use Newt25 for my calculations and have had wonderful results in my 8" f/5. One problem with baffled Newtonians is with air currents inside the tube. As warmer air rises along the tube wall the baffles can cause turbulence and drive the moving air into the optical path, thus causing distortion of the image. I decided to use the adhesive backed flocked black paper available from Protostar(www.fpi-protostar.com). This stuff is far tougher than you would imagine paper could be, and works extremely well as baffling. It does take some practice to line the tube, however, so get extra if you decide to use it. You can also stick it on any reflective components inside the tube for far more effective blackout than paint. Once you install the stuff, vaccum out your tube with a brush before you install your optics, to prevent fuzz from getting on your mirrors. If you don`t touch it very much it won`t shed any more fuzz. I hope this helps. -Jason