I agree. I feel that the mechanics check(s) for the components should be rather routine. I would like a Will+Discipline check that gets harder based on the crystal related improvement but is still reasonable.
In the TCW cartoon, only one of those kids had any serious mechanical ability. They were all at the early padawan or initiate stage of their force training. I doubt they could have managed more than 3 to 5 dice to throw at a Will+Dicipline check and much less for a mechanics check.
Chances are those kids will use that lightsaber unmodified for most of their careers. There is nothing in the movies or cartoon that suggests jedi tinker with their lightsabers much over time. Most of them, seem to make maybe one or two serious changes to their lightsaber during their career. Usually as they transition from padawan to knight or knight to master. In those cases, I see the jedi creating a new lightsaber because they are stronger in the force not because they just graduated from advanced lightsaber metal shop.
In regards to that TCW episode, the kids were assembling a basic lightsaber, using an Ilum crystal with zero modifications, which the Beta goes out to say in the sidebar about lightsaber hilts doesn't require any dice rolling on the player's part, with the notion that the time spent to gather and assemble the necessary parts for a lightsaber hilt is already covered as part of the Negotiation (or Streetwise) check to obtain the item as you would any other item.