lol i was just noticing you said .25 and .50 so we're talking mm right?
because .25 mm = .010 in so .50 mm is .020 in and isnt too much to bore!
i though you were talking about boring it .050 in ! lol but anyway when you bore a engine, it's good to go with a lil as posable in order to keep your cyl sleeves [in honda motors] strong!
usually .25 or .010 is plenty enough to get any imperfections out of the cyls. though.