I think that instead of using one builder to upgrade something that takes a large amount of time, such as a Town Hall, You could ask more builders to help upgrade the building at an extra cost. For example, if I had 3 builders available and wanted to upgrade my Town Hall and It cost say 1,000 Gold (Just an Example) and it took 4 days to upgrade, I could add one builder for 25% of the buildings cost and it would take of 25% of the time. After adding said builder my upgrade would cost me 1,250 Gold instead of my starting 1,000. Also instead of taking 4 Days to upgrade it would now take 3 days because I have two builders working on it instead of only one.



