According to this post, you can create only one candidate block/sec for next block in general POS formula. Same in Casper? If it's different, how many candidate blocks can you create in a second in Casper?
The latest form of Casper, as I understand it, uses a different algorithm. At any given height, validators are selected in a random order to produce a block at that height. If an individual validator fails to do this in time, the network will allow the next validator in line to try.
There's not a concept of a "candidate" block. A validator may theoretically make any number of blocks when given the chance. However, if a validator makes a block that does not end up in the chain (a "dunkle"), that validator is penalized equal to the block reward. There's little reason to make more than one block.
For more information, you can read the Mauve Paper