cash game stack size strategy

[oldmangrimis]

I have a question and would like other take on it.
In a cah game stack size is not an advantage, just a diffrent game depending on the amount of BB.
and if i buy in short then i am forcing every one else to play my amount vs me. killing their imp odds.

what is a good buy in for this strategy. 20BB, 30BB, 15BB

thanks