Hi there Kiweevil, how're you doing?
I can really relate to this. I use Scrivener for the exact same thing. I need to write everything down otherwise I will forget. Scrivener has a mobile app version but sadly one needs to buy it separately from the Windows one so I decided against it. I can always just write it in my notepad or email and then copy it once I'm on my PC.
CSP is very popular indeed. At least a dozen people here that use it. textures.com sounds interesting. Might have a look at it later, thanks.
Have a nice rest of the day! 