chest 40 / 42 is the same size as my winter jacket, (it even looks similar) and that fits me fine, textile jackets are more adjustable than leather jackets.
leather jackets / jeans need to be a close fit for the amour to be effective too, where textile ones can generally be adjusted to fit a bit more..
they do tend to offer less protection than cow though, and the closer fit of leathers offers less drag, noticeably so at speed