I'm wondering what the optimal cgminer change management strategies are for multi-pool mining.  I currently mine on slush's and bitminter.  Specifically, my questions are:

1- Is it better to mine exclusively on 1 pool and keep the second as a fail-over only in case of issues with first, or to distribute the mining effort across 2 pools?

2- If one wants to mine on both pools simultaneously, then what are the differences between the following settings, and what's the current thinking on which is better?
     1: Round Robin
     2: Rotate
     3: Load Balance
     4: Balance


Apologies if there's already a thread on this.  Thanks.