Hi Shaun,
When I first started the D3 regimen Batch had suggested 100,000 IU a day for 12 days and then drop back to a maintenance dose of 15,000 IU/day with the oil-based liquid soft gel vitamin D3 formulations or 100,000 IU/week with the Bio-Tech D3 50 50,000 IU water soluble vitamin D3. Additionally you will need to take all the co-factors see below.
Here is a copy and paste from some of his protocol overview and the link if you want to sift through it as well:
https://vitamindwiki.com/Cluster+Headaches+treated+by+high-dose+Vitamin+D%2C+etc.+(interview+and+transcript)+-+Feb+2022
Hope this helps get you started!