Solved FT Piggyback

TLDR: I'm looking for information on the servo needed for the FT Piggyback.

I'm helping my kids build a Tiny Trainer with the plan that they see how they fly when hand launched and eventually get a slight feeling for how the controls work under hand launch power. Eventually I was planning on using the FT Piggyback to haul their trainers up a few hundred feet so they could release and glide them back to the ground. I've managed to find the plans Sp0nz has listed so I'm good there, I was really just hoping to buy this off the store but it seems that they stopped selling it? If they really did stop selling it, does anyone know the specs on the servo I would need? The only thing I can gleam from the Youtube episode is that it's a metal gear digital servo, maybe the size of a 9gram?

If the kit is in the store and my search skills just suck that badly, can someone share the link?