COMPRESSION CHECK THRU GLOWPLUG HOLE?

I am sure this has been gone over a zillion times,but I can't seem to find it! Can I just comprss chk thru GP HOLE,or do I need to go thru injector opening. I am just looking for a quick insight to the overall condition of motor, before I go do something normal( I mean stupid).

Yes that is what I used once in the past. I have a compression gauge with an adapter the size of the glow plug. Just make sure your gauge goes well above 400 psi, mine goes to 1000, or you might have gauge parts all over.