I can believe that Harimoto played this equipment when he was 11. He was already very advanced and strong. And at 11 he was almost a professional. but a viscaria, together with tenergy rubbers, is heavy in weight even for adults. can younger children handle it?
You asked about "young talents", which implies kids at the top of their age groups nationally who already play at a higher level than most adults, not just your average kid.
If you take your average kid or any kid and adult starting of for that matter, then it's best that they start with an ALL+ 5-ply all-wood blade with either Sriver, Mark V or slow tensor rubbers like Xiom Vega Intro. That's what most of the kids or adult beginners start with in France and most of Europe, and the ones who become serious about the sport develop really good technique and upgrade rubbers as they go along. Most of them never ever change their blade and still kill you with an ALL+ or OFF- 5-ply with whatever rubbers on. Not a lot of carbon players here until the national level.
Same thing in Japan, kids and adults start of with a Korbel or Swat with Mark V or Rozena rubbers, then perhaps move on to an Innerforce ALC etc.
In the US, most people and kids start with a Timo Boll ALC and Tenergy rubbers, doesn't seem to affect the kids too much, but the adults never seem to improve very fast and as much as they should.