Now that you've cleaned heat exchange surfaces, and ensured nothing broke apart, you can either measure thermal patch surfaces you need based on the old ones you took off your mother board, or use my measurements.

Here are the amount and dimensions, sorted by color, of each pad type I replaced. Regarding thickness, I used 1mm pads (from ARCTIC, mostly because their communication style and reviews seemed less fraud like). I would nonetheless suggest using 1.5mm pads as some surfaces from the heat exchanger hardly touch components on the left side of my board.

2 x Magenta - 6*14mm²

3 x Light Blue - 10*10mm²

4 x Green - 13*14mm²

1 x Dark Blue - L shaped with both sides being 7mm wide. Their length are respectively 21mm ( for long arm) and 11mm long (for the shorter one). /!\ Be careful to orient your pads correctly before cutting this one. Also, be sure to check how to lay down your pads depending of the brand (check here in the case of ARCTIC).