I have used the Lite Trail System a lot. To be honest, the windscreen and Esbit stove were okay; I’m not going to stress out trying to squeeze out a little more efficiency.
I finally got to the point where I just wanted to boil more water. I was happier with more hot water for additional hot drinks with my meals. I slept warmer and had a better frame of mind. 850-900 ml pot simply made my trips much more enjoyable.
I don’t think anyone is going to come up with an efficient Esbit system lighter than a TD GVP Keg system, other than buying a smaller keg from Dan Y. The “newer” kegs with additional ridges are much stronger now.