Setting the gasLimit and gasTarget

Miners and mining pools are awarded EGL's when they produce a block with a gas limit that follows the desiredEgl vote. Miners can implement a geth patch on their geth node to automatically follow the vote each week.
While the node is running, just send the node an RPC request with either miner_enableEgl or miner_disableEgl to turn following EGL on or off (IPC functions also available). EGL is enabled by default if its configured when the node starts.