Whether it is true to the game or not, this methodology has helped me hit from the rough. Here's my theory and method:
Let's say you are facing a 100 yard shot 30-40% buried.
First assume the middle ground of 35%.
Then subtract 10% from 35 since on any perfect lie your given 2-10% buried.
This leaves you with a figure of 25%. Now take your 100 yard shot and add 25%.
This gives you roughly a 125 yard shot. You may play it + or - a few yards depending on the pin position and bunker locations.
If I were given a 145 yard shot 40-50% buried. I would take 45%-10% = 35%.
35% of 145 is roughly 51. Therefore I would play a shot around 196 yards +-.
Hopefully this will get you started. If your not able to do math on the fly, I suggest you get a scratch piece of paper or go with the club up approach. Hope this helps and happy hunting.