good post...and i personally dont think there is a correct answer. it really does depend on the amount of players at the table, and the strength of these players. if you know there is someone on the table always limping in and catching, a raise of 2-3bb may push them out making your odds of winning that much better.

basically i think the answer to your question is situational. so your coin flip solution, although it seems crazy, may just be the most rational answer.