Seems like when your the first person to make an output on the new mining segment you get the reward for the set of 50 blocks.
This is how mining works: If there is no reward in the previous 50 blocks, start finding a txhash of which the first three symbols match your address
If you find them before anyone else, you are rewarded with 25 bismuth
If someone produces 50 blocks in order to receive mining rewards before everyone else, they should pay extra on the fees. Max fee is around 5, 5x50 is 250, which is 10x more costs than reward. At least that's the intention
You should get the reward instantly after mining it, unless the a node with more blocks than you mined it also, in which case it will reject it
I started a testnet diary: https://github.com/hclivess/Bismuth/issues/11