what's the difference -v 512 and -v 1024?
It's a block reward vote.
How it works
Intially Heavycoin starts with a zero block reward. The very first miners will have the first opportunity to solve blocks and vote on what the first democratically selected block reward should be. The first 100 blocks (3.3 hours) will decide the starting block reward. From then on, block reward voting will continue, but the votes are counted and averaged every 3600 blocks (5 days).
Heavycoin is configured to mine and vote by default, with a default vote of 512 HVC. If you want to change your block reward vote then see How to vote and RPC voting. Otherwise, to disable voting then see How to mine. When mining is enabled, every time you mine a block your wallet will automatically cast a block reward vote. The Heavycoin network automatically averages these votes every 5 days (3600 blocks) and sets the new block reward accordingly. The block reward is the average of all 3600 votes over the previous voting period rounded to the nearest integer.