How do I adjust a bread recipe for long, cool proofing? I've got that recipe that calls for 21g of fresh yeast for buns that shall only rest for one hour: https://translate.googleusercontent.com/translate_c?depth=1&amp;nv=1&amp;rurl=translate.google.de&amp;sl=de&amp;tl=en&amp;u=http://www.chefhansen.de/2013/10/07/the-golden-october/&amp;usg=ALkJrhjEB2ncHCn-QroNukS7DWPli2tLBA

If I want to proof the dough overnight or for 24 hrs, 48 hrs etc: how do I need to adjust the amount of yeast to use? Is there any rule of thumb to apply?

Edit:
The ingredients for the buns are:


250 g Hokkadio Pumpkin
50-75 ml of milk
21 g cube fresh yeast
150 g wheat flour type 550
360 g whole wheat flour sifted, remove the bran for later
1/2 tsp caraway seed
1/2 tsp fennel pounded
2 tsp salt
60 g butter
Seeing the recipe now, my only advice is: don't. 

Long proofing is something which is done with white wheat bread to add some aroma. And it depends on the yeast having very good growing conditions. 

What you have here is a quite complicated dough. It has a ton of pumpkin in it, and most of the flour is whole wheat. And then you are adding spices, which have yeast retardant properties of their own. This is a dough which will have trouble rising. Keeping it alive for 24 hours won't be too easy, getting a decent rise out of it will be worse, and getting good added taste instead of some off tastes with this mixture is in the stars. 

And even if you managed to proof the dough well in a long process, you won't get the effect you are hoping for. In pure wheat, a long fermentation gives you subtle fermentation aromas, but nowhere as strong as sourdough, and a very specific texture which people tend to seek out. You can forget the texture in this overloaded dough, and the spices will cover the taste change pretty much. 

Just use the recipe as intended, and if you want long-fermented bread, take a recipe which is meant for that, there are enough of those around.