Just FYI, measuring by volume can be a pain. I know you said you can't measure weight now, but I'd recommend measuring by weight whenever possible, and it can be done on the cheap. I got a small digital scale at Target for ~$10 or so and it does the job nicely.
Keg #1: - Hefeweizen
Keg #2: - Mild Ale
Keg #3: - CO2
On Deck: Black IPA - Imperial Stout - IPA or Double IPA - Mocktoberfest