Excel 2007 : How to automatically display "best measurement"

First, what I am doing:
The usage is on a chemical calculation sheet, in which several factors are calculated. The result is along the lines of "add 1,400 grams (4 1/4 cups)". The grams are for logs, the cups as easy common measurements (especially as each chemical weighs differently).

I am looking for several things here, however:
I would like the common measurement to display either tsp, tbsp, or cups, down to fractions of 1/8. Preferably, the fractions would be reduced (ie. 1/2 instead of 4/8). Displaying 3rds along with the 8ths would also be okay, as the scoops do include 1/3 cup, but I don't want anything odd like 3/5 or 1/9. I also don't need mixed measurements (ie. "7 cups and 4 tbsp").

Can anyone give me some pointers on how to go about this? Is it possible to do all this with just a long IF formula? I could do the measurement selection easily enough (tsp/tbsp/cups) based on amount, but I'm not sure how to go about restricting and reducing the fraction display.