Well, heres how I would go about it...
I'd Set up light and give the area a very fast sweep...10 minute quick scan in full tones to know what I'm dealing with and where the primary/secondary/tertiary pay dirt drop zones are...
Then, I got an idea of the depth of the targets, their composition and the locations layout...and I can set up appropriately and get to work! This is where a really fast target retrieval method comes in very handy...a screwdriver and a serrated blade knife life a steak knife...
You make one rip through the sod and wow out a fast hole underneath it to get the deeper targets...you dont have to dig like with a conventional tool and pop out a plug...not here in Michigan, its pretty much all sand/loam and easy excavation work...
You got one shot on a time sensitive location? It would be nice to put it off until November when the ground is wet and the grass is flat and the weather is cool enough to really put the blocks to that old Mutherhubbard! PRIME overall conditions!
If you have to do it Now, like this week, the dirt/weather conditions are not optimal...but hey you gotta do it anyhow...hunt fast and hit as many targets as possible within your short window of opportunity...do not diddle around and take pics or look at the finds or think too much, just rock that dirt for Old Glory as fast as possible! Thats what I'd do...
You can call and I'll come on over and give it a quick broom on my way to the beach...! A guy will know within about 5 minutes if somebody beat you to that spot and cleaned it out back 20yrs ago...