for reference, the way you get photoshop to give you a .act file that is organised how you want:

• get all your colours in order etc
• add them to your swatches in order
• go to edit->preset manager->swatches
• select your colours then save somewhere you can find
• this creates a .aco file (photoshop’s swatch format)
• now to make it into a .act file
• have a psd open, doesn’t have to have anything on it, it’s not super important
• image->mode->indexed colour
• this changes it from using theoretically any colour to using a specific palette
• under palette dropdown, select custom->load
• change file type it’s looking for to .aco, select your .aco file
• save as .act