On the button with 3 limpers

Grae

My question is this...

When on the button how if I would normally open with 30% of hands with at least a 3x bet against weak blinds that I know will usually fold to the raise.  What % of hands should I be dropping with three limpers before me.  I have found that if I raise from the button most of the limpers will call.  Should I be raising more for each limper in the pot or tigthening up my opening to something to say 15% of hands and raising more with this range of hands?

sikas

3x + 1bb per limper +mayb 1 more bb for good measure with perhaps a 12% range