The corner is likely going to see the most wear, so you could argue a bit off the bottom and a bit off the sides might be most efficient in getting to sharp with minimal material removal. Doing the end in this context means a few thou, its not heavy re gouging and reforming the end geometry like you'd have to do if you cut off the bottom 1/4 or 1/2" inch.
When you do then helix, you are supposed to do the end as well if you're doing it as service for someone. For myself, I mostly skip the ends if it looks good after doing the pheriphery; after all the bottom is only used when plunging....not something I'm doing on a manual mill. Keep in mind the bottom of an endmill also isn't supposted to flat, the bottoms angle in a few degrees to the centre.....so on an endmill that hasn't beem plunged straight down, tuning up the periphery should be good as the bottom doesn't see much action. On my cnc, where there is lots of plunging, I'm using insert type chippers.