use only tube type fittings
use only the long radius bends and you will be fine. The ones that are problematic to flow are right angle drilled and do not have a bent tube between the hose end and the AN nut end. The drilled fittings cause eddy currents that slow the flow in the line. You should minimize the use of any sharp bends and angled fittings for optimum flow in any oil or fuel system alike. Two 90 degree elbows with gentle bends on your adapter is a common plumbing practice.
Bruce