Even just 30-60 seconds in KRST 1+20 is enough to reduce any funky cast left by the development process.
Selenium toner itself has the notion of a snatch point - it'll keep cycling in and out the longer the toning process goes on, where the "cycles" will reduce in intensity as the overall tint approaches colder magenta as the ultimate cast. Grabbing it at somewhere around 90-180 seconds usually works well, but it can also be used longer as a utilitarian to lock in shadows and bottom mids such that a successive toner (brown for instance) has less silver to affect. This doesn't necessarily need to be for a crazy split-tone goal, but instead to help control polysulfide or sepia toners.
Remember too that KRST can also be used the same way but instead followed by bleach to punch up mids/highlights without affecting the shadows - a form of chemical expansion.
Stop worrying about grain, resolution, sharpness, and everything else that doesn't have a damn thing to do with substance.