The approach you describe is completely fine and in fact it's what most players would do. Nobody really has the time and skill to calculate exact pot odds or probabilities at the table, so what you do is memorize some basic probabilities (such as ~16%, or 1/6 chance to hit open-ended straight on next card) and compare to your pot odds. It can be helpful to know both what your chance to hit an out on the next card is as well as your chance for hitting an out on the next two cards in case you're facing an all-in decision.
After you're done playing a session, it can be helpful to then go over some of the hands that you weren't too sure of at the time and put down some exact numbers and do things like calculate your hand's equity versus various ranges of hands that your opponent(s) may have had. By doing that, you'll get better and better at having an intuitive sense of odds and how to play certain hands.
Edit: On re-reading your question, it seems you're just asking if using percentages rather than x:y odds notation ends up conveying the same thing. The answer is that yes, they give the same result every time. For reference, check out this question.