Yes, when I say "480mm" or "600mm" I mean total rad length of all rads. I have 1 240mm and 1 360mm. What you're describing will be plenty.
That's great, now what type of tubing would you recommend? That's all I'll need to decide on before I begin planning out the loop and decide on fittings.
That's up to you based on what you want your build to look like. You can get soft tubing or rigid tubing. I'd go with PETG if you do rigid tubing, much more forgiving material.