I cant understand how he can still hit that target without taking arrow length, spine weight arrow weight and draw length into consideration, even when I do the maths with my modern recurves I'd still struggle to make those shots..
For exactly the reason mentioned above.
Too much info,too many things in your head,I'll bet he shoots totally instinctive.
When I was a kid a mate of mine whose father was an archer had tried to get him interested and had bought him a cheap fibreglass bow as a starter. He just thought it was boring so he swapped it to me,I cant remember what for(remember swaps,do kids still do that).
Anyways,that bow and four arrows went with me every where and in a very short time I could hit things not 100% like the chap on the film but certainly 90% of the time.
Same sort of sizes as his target and same sort of distances.
At some point the bow got broken and I forgot all about it.
Some years later with the memories of the good times had,I decided to join a club,a well known one in Surrey where the coach is a very well known teacher at all levels.
I told the story of playing with my fibreglass bow as a kid and shot 6 arrows.
After 20 years it was going to take more than 6 to get my eye back in,but I was told everything was wrong from my stance and grip to my draw length.
So suitable adjustments were made.
Guess what?? Yep I have never been able to hit a barn door since.
Must be a moral there somewhere
GS