Exactly, if I came from 10k no way i'd only be 50 mph faster, fact I dropped from 2k above him to start with he had plenty of E instead of merging he ran his mouth on 200 and gave me his 6, that was his mistake. Secondly as you said - He extended away, I gave him the advantage of a co-alt merge, he didnt take it.
As much as I agree that Cmustard is a total nutjob on 200 lol . You did have a totally dominant E position in a totally dominant plane , which you used very well to get the "norisk" kill . You dropped flaps and chopped throttle to get angles/position on him perfectly to finish him, when he was probably expecting another E pass. How many zooming/E passes had you made at him before the film started ?
It was a well executed kill, just wouldnt call it a co-E merge by any stretch (109K @ 355 vs f4U-1 @267 is a long way from Co-E).
In his position , I would have probably done the same thing - extend , build speed and try chip away at your E advantage, rather try to merge with you and have your K climb all over me at the merge. He just needed to be ready for when you dropped flaps and chopped throttle (which he wasnt - probably too busy swearing and kicking the dog).
Anyway - good kill .