12v with key on

I am wanting to wire some 12v keyed accessories in my Demon. What I would like to do is add a blue sea fuse box and run the 12v keyed source to it and then utilize the power through the new fuse box.

Is there any reason I can’t do this?
Where would you draw this keyed power from?
Is there a better way to do this? Relay or otherwise?

I am for sure adding Autometer gauge wiring and the contour fan setup needs to be powered from here too.

The fuse block will have at least 6 spots. I have a second one of these wired hot to starter relay for ignition, fuel pump, water pump and other items I want to be able to run without key on if needed.