The thickness of the coats is as follows:

scratch (rough sand, lime, cement) coat - about 3/4 - 1 inch
rough coat (rough sand, lime 2:1) about 1/2 inch
float (arricio) (finer sand, lime 2:1) about 1/2 inch
skin or skim (intonaco) (fine sand, lime 8:5) about 1/4 inch + second (skin itself) about 1/8 inch
(Intonaco is applyed in two coats with about 15 min interval)

see more in "Albuquerque Fresco" topic on wall and plaster prep.

>and had a kind of "cheesecloth" between

what you saw is mesh used to prevent plaster from breaking, see "Albuquerque Fresco" topic about wall prep and deduct from there for small panel.

>Howver I notice in the panel the Ilia is painting of
>the woman and child in the sun that it very thin

that was just intonaco, the whole panel is about 1 inch.