Raise sizing with multiple limpers

[Poker Clif]

My standard raise is as follows:

1. Standard is 3bb.
2. Add 1 bb if I'm in early position (to keep late limpers from getting good pot odds).
3. If there are limpers behind me, add 1bb for each limper (again, giving pot odds which don't make a bunch of limping/calling automatic).

So, if the blinds are 25/50, I'm in late position, and there are two limpers, I would raise 5bb (3 as the standard raise plus two for the limpers).

My problem is that at micro/low levels, where 5 or 6 limpers are not uncommon, a standard raise can get big real fast.

Example:

I start a PokerStars tourament with 1,500 chips.
Level 3, blinds 25/50, and my stack is still around 1,500.
I'm on the button with 6 limpers behind me.

So it's 3bb + 6 limpers = 9bb raise, which is 225, or 15% of my stack.

It seems mathematically correct to account for limpers when I raise, but if I do that two or three times and don't win the pot, my stack has taken a huge hit.

I guess I could look at this one of two ways:

1. If that many people are going to limp or call, perhaps not even understanding pot odds, I should probably scale the limpament raises back a bit.

2. If it's mathematically correct to do it, then I should do it, period. The occasional huge payoff from having so many in the pot against my legitimate rasing hand is worth the risk of short-stacking myself when my pocket tens don't hold up.