That's correct, you could apply over fiber reinforced Rasolite base coat or Arenino directly with addition of Vimarlatex 663, 1L per bag of Arenino thin coat.
PS. We just reduced the price of fiber reinforced Rasolite from £11 to £10.25 and Plastex GB1 from £11 to £10 thanks to significantly increased sales in both products and therefore economy of scale.