I'd say there are too many numbers floating around on this. If you add working out your crosswind at limits, you are overloading yourself. My own technique, from 747 to 737, is to listen to the proximity of the radio alt calls to judge flare strength, along with taking into account 'girding ones loins', and any gasps from the copilot, and any other visual cues. It works, without too much clever calculations and focusing on one thing only. Whenever you do that, something else creeps up and sticks it to you.