STUD1Y
+1y
The slow point is the smallest hole.
If you're running a 3/8" system, to get everything to be as past as it possibliy can, all the I.D's have to be 3/8" at the least.
So, on 3/8" DOT Line the inner diameter is actually about 1/3" inner diameter.
so just try to upgrade the lines. maybe it will be noticable.