Quick q on late extract additions: how little can I add to start?

In about an hour, I'm brewing a west coast IPA with Pilsen Light DME. I want to add as much extract as possible at the end so as to not darken the beer. So I'm wondering what the smallest amount of DME I could add at the beginning without problems? 2lb? 1?

Just for my own interest, I wonder why a malt addition is needed at the beginning at all? Any thoughts?

Thanks everyone.

Whenever I do extract, I typically do 25/75 regular and late addition, and don't notice any appreciable color or hop utilization issues.

Everything I've read states that you need to have at least 15-20% of the fermentables in the normal early addition, as those sugars and enzymes aid in the release of hop acids/oils to allow consistent hop utilization. Hop utilization goes way down if they are just in water.