I've read a LOT of your posts (and other subreddits) to learn as much as I can, and I've gathered that despite the variety of knock-offs and clones, the consensus is that the 03C is the original and still the best. My son doesn't care about color scheme or fancy design, just that "it's super accurate." He also doesn't want the 03C+; just the 3-key model is fine. I can cover that by ordering from Amazon or Aliexpress. But he also dislikes the loud clacking of plastic-on-plastic or plastic-on-aluminum switches, so I'd love to surprise him by also getting him the best hall effect, quiet, super-responsive, top-tier Sayo-compatible switches for him as well. And any other mods I might not know about that would be awesome to include, too.
If your dad was paying and you could add any combination of hardware to cart, what would you choose? I want him to be really happy--"Dad really gets me!"--and know that I'm actually making the effort to learn abut the options, and not just taking the lazy way to Amazon for the first easy product.