hmmm, i loop mine. but honestly i dont' know if it circulates, what I did was use a simple flush T fitting from autozone for $1.
my two buddies also loop, but they both use something like this (oil/break reservoir for a motorcycle), what they did was use a simple 3 nipple T up from the loop to this little container and mounted it against the hull.
I plan on switching mine from the simple flush fitting to the reservoir next time I get bored enough to go on fleabay and order one, for two reasons.
1) larger amount of spare oil.
2) much easier to fill and check levels.