Well as honesty is key for this type of thing, your best bet isn’t a KRK which are often bass heavy to make them sound better. Depending on your price range, I would recommend you start looking at Yamaha’s and Adam’s monitor speakers then move to the likes of Focal, Fostex and Genelec. I doubt you’ll be able to afford “the best” monitors for this because it will largely depend on the price you are willing to pay. Any I mentioned above are very reliable monitors for this kind of work.