I understand that, with BIP 100 as suggested by Jeff Garzik, in the first step the maximum block size can be increased from (then, after the hard fork) 2 MByte to at most double of that, so 4 MByte - without a hard fork. Depending on the miner's votes (counted for 12.000 blocks, 75% majority necessary) the block size may be increased further.
How can I, as a user start the voting process? What if I'm a miner? How do I determine the new maximum block size? Can two votes for 3 MByte and 4 MByte run in parallel?