Only stuff I think Todd Krueger teaches nicely and very easy to understand is how to calculate the square of nine using a regular calculator, the rest of his stuff is extremely basic and weak (the wyckoff stuff).
I shared van Dam's courses in a thread in this forum, but I have no idea where that thread is, so here is the link to Lex van Dam's four courses:
[spoiler=Gift]Link: https://mega.nz/#F!9pJ1UDgI!AtdvD2NYH79-y7NVhjzW3A