Considering that capturing the Golden Snitch should be a difficult task in every game but it should also be catchable by the players (or the game wouldn't end): are all snitches made equal? Do they adapt themselves to the skill level of the seekers?
And if they do scale: how does that work?
In other words: would Viktor Krum have the same difficulty catching the Snitch in the Quidditch World Cup finals than in a regular Hogwarts game?
There is no mention of scaling regarding the snitches.
However, both teams can work really well as scaling the task. Especially one team's ability to hit the opposing seeker with bludgers would be fairly significant in making his job harder, thus giving an edge to their own seeker. An edge that might be opposed or even flipped by the other team if their skill was comparable or greater.
Also, maybe the author didn't put more thought in that aspect of the game. Indeed, I think the perpetual increase in equipment performance might have an even bigger effect on the game than the team's skill, just looking at how notable the iterations are in the books from one model to the next.
It seems unlikely that the Snitch adjusts its own difficulty to the specific two opposing Seekers playing the game - otherwise there wouldn’t be any matches that drag on because the Seekers can’t catch the Snitch, and Harry wouldn’t be able to catch the Snitch in the first five minutes because the Snitch would’ve made it harder for him.
It’s possible that there are Snitches made with “innate” levels of difficulty, that wouldn’t scale to specific Seekers, but would naturally be a certain difficulty to catch. For example, there might be a Hogwarts-level Snitch, a professional-league-level Snitch, and a Quidditch-World-Cup-level Snitch, since it mightn’t even be possible for a Seeker at the lower levels to catch a Snitch intended to evade capture by world-class players.
Snitches definitely aren’t all the same speed. That much, we can see. Ginny mentioned that the Snitch she caught during a game at Hogwarts “wasn’t a very fast one”, which shows that all Snitches don’t always have to fly at the same speed. That Snitch was still considered usable, and Ginny didn’t seem to find it particularly odd that it was a bit slow, so it’s unlikely Snitches have to fly at a standardized speed.
“Good catch,’ Harry told Ginny back in the common room, where the atmosphere resembled that of a particularly dismal funeral.
‘I was lucky,’ she shrugged. ‘It wasn’t a very fast Snitch and Summerby’s got a cold, he sneezed and closed his eyes at exactly the wrong moment. Anyway, once you’re back on the team –”
- Harry Potter and the Order of the Phoenix, Chapter 26 (Seen and Unforeseen)
She seems nonchalant about the Snitch not being very fast, not surprised like would be expected if this was a particularly unusual occurrence. Instead, she considered it fortunate but not shocking.
