Well.
In order to not "burn out" on painting one colour on a horde of models, I separate them into groups (like 10 groups of 3 models, for example).
I then paint the flesh Sunburst Yellow on the three models in group A.
(This is my first pass)
I then paint the flesh Sunburst Yellow on the three models in group B, then apply the Ogryn Flesh to group A.
(this is my second pass)
I then apply Sunburst Yellow to group C, Ogryn Flesh wash to group B and then drybrush Sunburst Yellow to group A.
(Third pass)
I then paint Sunburst Yellow on group D, Ogryn Flesh wash to goup C.....and so on....and on...and on.
This allows the washes to dry on the previous groups, so I can continually keep painting.
Keep in mind that on the first and second pass, the wash might not have time enough to dry, but on the sixth and onwards it will.
Remember you can be as sloppy (and quick!) about the Sunburst Yellow, Ogryn Flesh wash and Sunburst Yellow drybrush as you like. The carapace will be repainted in Bleached Bone anyway.
The above method is especially good if you are using a wet palette, as the various paints on the palette don't dry up between passes.