The answers are contained in my post right above, but I'll pick them out for you.
If you choose to do it this way, it's really important to let it ferment COMPLETELY before refrigerating it. Refrigerating is important to make the yeast go dormant and fall out of suspension, so that when you pour most of the liquid out, you're not pouring out significant amounts of yeast as well. Before pitching, swirl the container a bit to mix the yeast back into the remaining liquid so that you can pour it. The reason you need to make sure you let it ferment out COMPLETELY is that it is only when the food starts to run out that the yeast starting building up their glycogen reserves, which will be important for the yeast to have access to when they come out of dormancy and start reproducing.
It will take a few days to ferment completely, and I prefer to give it at least 24 hours in the fridge (it can stay there for up to a week - and if necessary, two - but I try to use it within 3-4 days of refrigerating). So I wouldn't expect to be brewing on Sunday. You could possibly manage it if you made the starter RIGHT NOW, and pitched it very late on Sunday night, but that's far from a guarantee.
However, 2 liters isn't necessarily a big deal unless you're brewing a very light, delicate beer. With most beers, I wouldn't obe concerned at all. I would likely just go with your original plan and pitch at high krausen, but it ultimately depends on the recipe you're using (though the style of beer you're brewing is probably the only information really needed).
Wow emjay thanks for the great insight. Brewing an IPA by the way. I think because of time constraints I'm just going to go ahead and pitch at high krousen. I was just originally concerned with such a volume of starter going into my wort. And I will make sure my starter OG is in check.