Typically our speakers round-overs are 3/8" or 1/2" but the larger the round-over, the smoother the response will be, but eventually, you will either need extra material in the inside corners or thicker baffles to prevent opening a hole because the material becomes too thin, or you have to move the drivers further away from the sides to accommodate a larger round-over.
Where it matters most it when the tweeter is equidistant from the left/right sides, (or even worse: top & sides are all equidistant) as you have 2 diffractions happening and arriving at the same time, where they may arrive in-phase (a peak, or out of phase (a dip) the larger the round overs.
Having drivers off-set, like the Brute/Bully is much less of an issue as the distances between the tweeter and the edges are all different, so no one diffraction is cable to couple with another, and the effect is much less of an issue.
in the case of the Brute/Bully, having no round-over won't wreck the response or the sound overall as it might with some other models but, rounding over the left/right sides is recommended at a minimum.
An example of really bad diffraction is the Dayton Opal 1:
https://youtu.be/eYMihmM81lI?si=Hyc-M91ihUoutLUwAnd the SVS Evolution bookshelf:
https://youtu.be/Gs3F66JIcgI?si=7UGVCKknyn78wHnCThe first part of the SVS video has a really good illustration of how the baffle shape affects the speaker's response as its shows a prototype tweeter & mid pod in several custom baffles and how it affects the response.
