I’ve mentioned before that buying an engagement ring is a highly subjective choice. Women usually have a good idea of what they want and if the groom gets it wrong, their fiance may be too polite to complain whilst thinking ‘ugh, I have to wear that for life?!’
Save yourself the trouble guys and propose with a knot ring. She can transfer it to another finger of keep it as a dress ring after you’ve both gone shopping together for the real deal. Easy!