I find the EY "Chinabuckers" a bit clearer and articulate. They sound like a Thunderbird to me, but I don't have a 60s Bird to compare,
I don't have a bass with Thunderbuckers either, so I can't compare to them. I got my pickup rings with the pickups, but bought spacers from Thunderbucker ranch. You may find you need spacers as the EY pickups are quite shallow.
I have some Ken Smith Bass Burner strings on order, which will allow a better comparison of the Thunderbucker with the Chinabucker. Until then ...
The Thunderbucker definitely has more output than the Chinabucker (and I have the 9K2Ω in the neck position). Compared to the Thunderbucker, the Chinabucker is sort of 'polite' - missing a bit of top end, articulation and snarl.