I made a few of these. I hooked one up to the orifice and counted the
seconds it Took to get 11 inches of water colum. Then I cleaned the orifice
with ACIDDDDD. and counted the seconds,again. I got the same count as the
new orfice I once used used. A clean orifice makes a big difference,and
alcohol wont remove oxide of brass. I got the same count after using
alcohol.  In the endm,the tube diameter dosent make a difference.It only
takes longer to get to 11 inches if a large tube is used.A small diameter
tube gets to 11 inches quick.