In terms of lightening, the heaviest items are action, stock and barrel. Not much you can do to a Mauser action to lighten it - the G33/40 is about the lightest stock Mauser action (small ring, lightening cuts in the sides, etc.) and it is only a couple ounces lighter than a standard large ring Mauser. Drilling holes in the magazine will only lighten it by a fraction of an ounce and is probably not worth the effort unless you're looking for every little bit.
Switching to the 2 piece Talley lightweights should drop the weight by 3-4 ounces compared to a one piece Leupold base. If you have a heavy scope, a lighter scope will lose a few more ounces (e.g. a Leupold in place of a Zeiss). If you're only looking to lose a few ounces overall that may be enough. A lighter stock could lose more weight. You may want to try that and see how the balance is before going to tapering the barrel, as that is an irreversible choice.
