WoW this is fantastic! 4K83 looks really good in 720p and the ending is perfectly edited.
I think SparkySywer was doing it in a different way. Besides using Harmy instead of 4K83 (i personally prefer 4K83) , if i am correct he is using 97 only for the Tatooine-Coruscant transition, using BR for the general Bespin, Tatooine and Corusant scene and First Endor shot ( so It has the edited Jedi Temple and Senate) and I dont know how he managed to change from the 97 transition to BR Coruscant without being noticeable but that is also good.
I personally really like how that test video looks, but maybe is possible to put BR since Luke in front of the pyre, then Bespin BR then Tatooine BR , then 97 Tatooine-Coruscant transition and Coruscant , then BR first Endor scene ( that i also see very blurry specially in the sky in your 97 version, i suppose that is inherent to all 97 versions avaliable due to SD). Then continuing exactly as in your edit.
What do you think?
I dont know if that is possible. Personally, i think how you did It is really good but ofc it would look more HD if is possible to replace Tatoooine, Bespin and the first Endor shot.