When a film has an UNUSUALLY TIGHT CURL, beveling the corners makes it even harder to load because the beveled corners more easily spring out of the channel. This can make loading nearly impossible.
If you do bevel the corners the bevel should be very small, no more than 1mm x 45 degrees. Thatís difficult to estimate in the dark. In this case itís better to leave the corners square as they are more likely to keep the end of the film in the channel of the reel during loading.