Well, again, I think that is totally up to you to decide. People here have told me putting lead in the throat does nothing, yet I like the way it swings w/ the weight there, as opposed to distributing it at the handle & at 12.
Also, I don't really care for the feel of leather either, which is why I get a smaller grip size, replace w/ leather, then add an extra overwrap. The extra overwrap (a) adds an extra 5-6g, and (b) softens the harshness of a leather. While its not 100% synthetic feel, it is extremely close.
So, buying a 4 1/4", replacing w/ leather + extra overwrap, gets you to 4 3/8", but also adds ~ 15g to the handle area (9g for the leather, 6g for the extra overwrap). This gets you to 300g without adding any lead.