Spot on, have got it working as per your suggestions.
It's obviously not as simple as using the % by extract method as described in DGB
(i used to be able to do that on brewday with a pen and paper)
I have had a mate help me add this functionality to the brewing software i use,
so now i can formulate recipes by keying in percentage values of the grain.
I mean sure its fun calculating that out everytime but i'll just let the software do it for me from now on :P
Can't really thank you enough.