One last question before I get designing....
Click image for larger version. 

Name:	8x4.jpg 
Views:	294 
Size:	96.4 KB 
ID:	4489

As you can see by this image the sheets of 8 x 4 I'll be cutting get used almost right up to the edge of the wood. I will obviously need a frame which is larger so the router will be able to travel past the edge of the wood, I'm thinking 9 x 5 does this sound about right?