Weather-proofing a projecting brick course

[foxhole]

Hi all - as I am about to embark on a roofing project, my research brought me to this website which I have found informative and hilarious in equal measure. Hence I thought I would reach out to get the guidance of roofers and leadworkers alike for my following dichotomy. Below the parapet of our house is a projecting brick course, which when we arrived was covered in moss, damp, and darkened with weathering. I am considering running some lead flashing over it to ensure there is no ingress, but have a few questions that i would welcome your thoughts on:

1. What code lead would you use?
2. Should the flashing start 2 courses above the projecting brick course?
3. I assume the lead should be run in 1.5m strips max?
4. Where the lead laps should it be folded back/sealed in some way?
5. How should the lead be held down to avoid it lifting/flapping around in the wind? Leadmate, or fix a batten below the brick course and use lead dots? Is there a risk fixing with dots that you risk the lead tearing over time?

Ive attached a few picks and profile drawing of what i am considering. Thanks in advance for your time and attention - d.

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You appear to be asking for a way of applying your solution to a problem which does not exist.
(Happens quite a lot here.)