If you don't have shutoff valves, the check valves would screw into the manifold. If you have shut-offs and can do it, I'd put the cutoffs into the manifold and the check valves into the shut-offs.
Remember one unassailable statistic, as explained by the late, great George Carlin: "Just think of how stupid the average person is, and then realize half of them are even stupider!"
"I would like to die on Mars, just not on impact." Elon Musk