To me, it is not worth going this route. Because the culture buildings that benefit from this policy are relatively late, they get built pretty quickly without using a valuable SP to shave a few turns. Are you delaying finishing Rationalism before ideologies or after ideologies? If before (that's a rare luxury), then the cost/benefit is a few turns of production vs. +50% from RA's AND whatever random opener benefit you might choose. I don't think it's close. If it is after ideologies, then those buildings should have long since been built to get much benefit. Is the 25% GWAM bonus (+ maybe Uffizi) AND cheaper cultural buildings worth more? I guess it could be situationally, but you did say "when not going for CV".