The washers UNDER the intake flanges are a sign of something NOT right!
His intake flanges are warped.
They need to be machined to be perfectly flat or the intake seals will not seat properly.
No matter what type of seals you use.
The washers will do nothing but exacerbate the intake leak.
The flanges are warping with those blue gaskets and are not capable to squeeze them, that is why I use the washers. I measured the necessary thickness to offset the flanges so they will squeeze the blue gasket just enough but not to be bended around the gasket significantly.