Kind of weird that they went for the XHP35 here, I see no advantage over a XP-L or XP-L Hi. Perhaps the need to boost the voltage makes it easier to regulate the output?
I tested a 80CRI E17A actually 3 years ago: Nichia E17A/E21A series (April 19th: updated with output tests in the OP) . And Clemence sells some neat colour versions of the E17A.