Eric - went and had a look into this because inquiring minds want to know. Here is a web site regarding this: https://www.quora.com/What-is-a-%E2%80% ... p%E2%80%9Dericheath wrote:So the 1000 gets about 9% more curtain area due to its 38mm intake valve to the 1200’s 36mm intake valve.
The 1200 gets 15% more curtain area on the exhaust side.
I wish I knew which is better and why, but my guess is the greater exhaust flow and more overlap helps pull more intake air in yielding a better low rpm performance.
According to the article, you are spot on with a little extra clarification. There is a host of articles for this, but your short answer is good enough for me. I think the optimizing of the air charge in the cylinder according to the article only suits the original design intent, don't know what it will do when used as a mod to another engine design. Won't remember what I've read or found until I need it at a later date.
Cheers