I've been rocking Krux/Grindking kingpins in Indy's and then Thunders for the last 5 or 6 years. While I prefer how low those inverted kingpins are versus these Royal/Film style kingpins, it is convenient to be able to use a normal 9/16ths wrench to adjust it.
That said, with all of this discussion about how
hard it is to find an allen key that works with these kingpins. If they are like GK and Krux, they will be a 7/32 inch allen. I feel like at least at first, Indy might include a allen wrench with it like Krux did when they first introduced the Downlows back in the day.
But, if they don't, consider buying this Pig tool. It's the best tool I've ever had honestly, and has the 7/32 allen built in. Plus with a 3 prong wrench instead of the 2 on a standard Unit tool, you can get more leverage when setting up your board too. Plus, axel re-threader!