I would remove all the plugs, pick a cylinder and put your finger over the glowplug hole, and feel for the compression. You should feel it through the prop and the plug hole. Two rotations and you should feel the compression when you see both the rockers even. When they are even with the piston at the top, the lash should be checked. When piston is going up on the compression stroke, you will feel air try to escape; turned backwards should feel suction through the plug hole when rockers are even. If they are not even, keep turning the prop till they are. With a new engine, valves may close up faster while the seats seat. Repeat 6 more times. I like using denatured alcohol, also called methylated spirits, to free up engines as it desolves the gunk. You will need to oil the engine with some after run oil if you are going not run it very soon after cleaning it. Cant hurt no matter.
Also engines breaking in tend to destroy glowplugs from the small metal particles that come from the break-in. That stinks with 7 expensive ones. They may look good but can be bad. I would put each one in a single cylinder engine and make sure it runs flawless.