Howdy and thanks for your responses thus far. I am going to stick with the 8x10 and a focal length of 170. From there, I will play with different diameter holes.
As for film holders, it nearly appears that where others live, they are a 5c a dozen! OK, maybe not quite, but around here they are not necessarily gathering dust in every second garage. If there are more cameraís in the future, Iím sure I could come up with one to suit a 4x5 holder (which makes more economical sense if I want to use film). Also, this is kind of an exercise in playing with power tools as much as taking photos (Geez, Iím starting to feel like Tim Allen all of a suddenÖ.must go and find a raw steak smoothie). I must, though, resist the urge to go and buy new materials! I checked last night and found that the majority of MDF I have is 12mm, so itís going to be a chunky unit! (My Ďotherí hobby for a while was slot cars. I built a slot car track out of MDF, hence why I still have a bit laying around)
So, tonight when I get home from work, Iíll draw up some plans and see about making a start on the weekend.
I do have many more questions in relation to using paper negís, but I am sure that these can wait (donít want to put the horse before the cart!)