I've tried that racquet--a friend of mine has it. If I were using it I'd keep those 4 grams at 3 and 9 and change the grip to a leather one to weigh down the handle. A Head leather grip in place of the synthetic one will add about 15 grams; Volkl or Fairway leather will add a bit more, and most other leather grips a bit less. With an overgrip on top of it (7 grams), that's already 22 grams added to the handle without having to mess with any lead tape. With just the grip change it should be easier to swing fast and be more stable. Also, leather seems to absorb vibrations in a unique kind of way that I like. Can't quite describe it, but to me it makes racquets feel less "tinny" or "hollow"
If you still want to add lead to the handle, I would test it first--without removing the adhesive backing, try hitting with lead tape tied onto the grip with thin rubberbands first, moving it around, adding and subtracting to figure out what feels best (how much and where on the handle). It takes a lot of trial and error. I find that even two racquets of the exact same model respond differently to lead positioning (babolat quality control??), so there is no set formula that works best. and then when you know exactly what adjustment you like, then remove the grips and tape the lead onto the bare handle. If you can't feel a difference in your hitting with the added lead, then you most likely don't need it.