Try 'hydraulic pressure drop' for elbows, turns, etc.
For the pressure drop of your waterblock, you can try a rough estimate based on Bill Adams articles (i'm not sure he has tested the Maze3 yet).
I'm currently mounting a new waterblock so i haven't got any time to dive into details sorry
There's plenty of material on the net - pressure drop in hoses is an old fluid mechanics problem. There are good manuals on that as well (try a public library).
If the mag3 has more flow for any pressure drop , then it's the pump you may keep.
You could aslo mount both pumps in series
Sounds mad but it has been done.