The link provides index #'s, but no actual formulas. (Though I suppose you could deduce the formula from the info provided.)
That said, it would appear from this chart that LSAT is worth at least twice as much as GPA for most schools.
Most schools almost certainly give LSAT+GPA most of the weight in any admission decision. I would guess that for most schools, LSAT is worth at least 50% of the total admission decision, and probably more, while GPA is worth around 25%, and the rest coming down to essays and soft factors.