If confinement is playing a major factor, it will show itself by good density testing procedures.
if using a nuke gauge (a sand-cone would also work, but don't try to test sands with a drive tube Hahaha),
take density testing at different probe penetrations. With surface testing (no probe penetration which is generally only a good testing procedure for road base stone), you may be failing because there is no confinement during compaction. But, after 2", 4", 6" and 8" probe embedment you may see an increase in compaction to nearly passing the test. And if you gently remove 4" and give a very flat surface for the gauge to sit on and then do a 8" probe embedment test, you may find that you have passed after all.
The overburden provides confinement during compaction. For very sandy soils (especially for a regional material i know as "processed fill"), i consider the 8" lift of soil that is immediately placed as a confining blanket and the target soils for compaction to be the previous blanket.
It's easier for the tester if the soil just passes from surficial testing. Soils that have confinement issues sometimes get false failing compaction tests as you can imagine from what i've described above. if you get passing tests on the surface (with 6" or 8" probe embedment of course), then the soil is probably good enough that confinement is not an issue and you'll need to continue getting surface passes.
I think with 11% passing #200 that it won't play to be that much of an issue, but keep this in mind if it comes up.