Adding weight to the sled: when to add more, and how to recalibrate?

I have observed that the top 4" of the stock remains perfectly accurate if I add extra pressure to the bricks (counteracting the lift on the bottom side of the sled as it tilts over the top of the wood). I also note that the Metal Maslow (and M2) both have beefier, heavier looking sleds. I note that others have suggested 40lbs as the “standard” weight (including router) for the sled.

My questions:

  1. If I add additional weight, will there be any unforeseen consequences? Maybe skewing the accuracy on the bottom by causing the top of the router to lift down there? If so, are there any corrections/ideas?

  2. When adding additional weight, what is the most efficient way to go about re-calibrating with WebControl? What specific settings/steps need to be re-done (aside from the test cut at the end?)