I have the 23 qt and my Dad has the 16. I've used both. Personally, I think the larger capacity is worth it for sure. If nothing else, I can pressure 1/2 gal jars in the 23 qt. Nice to have around from time to time. It is a bit taller, but certainly not enormous compared to the 16. Not going to make a big difference when in storage. And since it takes a little time to run a batch from heat up to cool down, the more jars you can cram in there the better. More than likely, you'll get the first one and wish you had two.
It occurs to me, use 800 ML instaed of a quart or a liter, but make the starter wort stronger, so you can add 200 ML of water.
So instead of a starter wort OG of 1.03 - 1.04 use 1.05 and dilute