Weathering Alclad II paint.

I've never had any issues using washes over Alclad.  Typically I play it safe and use pastels rather than an oil wash, but never had any issues.  I stay away from polished aluminium since only show birds are that shiny.  Using normal Alclad Aluminum /Dark Aluminum/ Duraluminum I can use a normal gray primer that I then preshade with browns and blacks to get the result I like.  Alclac is pretty translucent in light coats if you go slow you should be able to get the right look.

I have had that problem too.  The polished aluminum is indeed too polished for run-of-the-mill aircraft.  An easy fix is to just spray on another coat and put it on thicker.  The  thicker the coat the less polished it looks.  If you want to make sure, spray on a coat of regular aluminum.  The "white" aluminum looks VERY weathered- probably inappropriate for a 29- pics show them as being in pretty good shape, that being a very expensive airplane.