There are many, many opinions about how many holes to puch in your foil or where to punch.
It depends on what you are punching with. A needle will make the tiniest holes, a tooth pick a bit bigger and what is usually used is the attatchment to the hookah tongs, the metal long needle like thing. Those make even larger holes.
The problem with holes too small is that they can be blocked as you smoke by ash. For that, some people just make that many more¬† holes just in that case, but you could be defeating your purpose ifthey do NOT get blocked.
Also, how big is your bowl? Are you using a double 2 headed bowl which has¬† a very narrow diameter? Then you need to puch less holesfor sure in each foil. Maybe you area few friends smoking on a multi-hosed hookah and using one of the very,very big “party bowls” which Smoing-Hookah.com sells. You’ll need much more holes for that baby.
The “normal” sized bowl should have as many holes punched so that you get a good suction when you pull. Too little amount of holes and your shisha tobacco could burn. (You’ll see the smoke rising). Or too many holes and you’llhave poor suction.
Play around, experiment. Each tobacco bowl has its own needs. Suction is the key. Make sure that as fun as it may be to puch a lot of holws in the foil that you don’t do so many that you will have a weak suction.
Where should the holes be? The biggest percentageshould be in the very middle since the sides of the bowl are not as deep as you go further to the edge. I’ve often punched holes¬† on the very outside, but found the shisha burns there and thesuction weaker.
Punch more in the middle and out toward the sides but not to the edges. Again, experiment and see what is right for you.