That makes sense on the platings. I'm 99% sure the crack on this one was entirely on me and not the kit. For one, this kit was solid stainless so no platings. For another, I'd actually filed down the inside of the tub too much when removing epoxy that had dripped down in there, so the fit on the hardware was kind of loose. I actually had to drop some glue in there to secure it. The only way it could have cracked was if I'd tightened down the tailstock too much. I (perhaps stupidly) was not using any bushings since I didn't have any TBC bushings.
That said, I do wonder why more pen kits don't use thinner tubes. For example, the Gatsby Grande and a few other sierra-style pens use 3/8 inch tubes. Given that the twist mechanism and refill are exactly the same size for those kits and others like the regular Gatsby, sierras, siroccos, etc., why do so many of the later kits use a tube with a 27/64 inch diameter? The hardware ought to fit. And the difference in strength of the blank is HUGE. Not to mention that it would make it much easier to use thinner, vintage materials that are, in theory, wide enough to fit on a the pen but are sufficiently narrow that there's no way you can drill a 27/64 inch hole in them and have any sort of wall strength left in them.