artichoke was a curiosity of mine too. It was as if the decision to go raw depended on these old favorites.
getting riveted to the turned-off knob of the stove in my knuckle handling them without starving for that candle effect. It isn't romaine lettuce but it can be romanticized with a soak after the real heart salad parts aren't discarded, just used elsewhere.
The range of time (ha-ha) for this immersion to suction has a few variables: liquid and quality [i.e. if a juice, juicy?], toughness of of these "petals" to come out as a rose almost, room temperature. I give a day at least to transform. And I was diverted or converted!