Circle Track did a good article in their Sept. 2003 edition called, Where Air Goes… or Should.
By Jim McFarland.
I can’t find it on their site but I’m not a member so may be why.
It talks about using spray dye when flowing heads to represent fuel flow pattern and get an idea of what’s going on.
But as David wrote about hear,
Six Wet Flow Mistakes if you don’t know what you are looking for then all the equipment in the world is useless.