The phrase "more double-quick" is already an intensifier for the term double-quick, which means to move or work at a very fast pace. Therefore, the antonyms for this phrase would be words and phrases that denote being slow or taking your time. This includes languid, deliberate, leisurely, gradual, sluggish, unhurried, and even procrastinating. The opposite of being "more double-quick" is taking things easy and not rushing, which can be beneficial if you want to take your time, avoid mistakes, or savor the moment. Ultimately, the antonyms for "more double-quick" all convey a sense of slowness and a lack of urgency.