a different speedup idea.

if builders could build faster for times it'd be OP. But my idea is different and I feel is balanced.
First off a seperate building (builder school or what ever)
Second there is no timed speed up, each building must be individually "boosted".
Based on how many builders you sent to "builder school"
Huh?... ok so lets say I have a lvl 2 builder school. And a lvl 4 builders hut. I have 2 builders than can participate . More than one builder can be used on the same building however it cost more and massivly slows progress of other buildings being upgraded. Ex 1% 1 builder, 2 % 2builders 3 for 3 and 5% for 4.
This will have to be used wisley and would be used for to focus a big upgrade or a tower in timefor war.
This could be gold and elixar based. Ea person gets 1 hut at lvl 6 TH. More huts=gems