Aditionally: Also what amount would be required to cover 60 square feet.
West System advice was: From the information you have provided we feel that WEST SYSTEM epoxy may be suitable for your needs. WEST SYSTEM epoxy can be used for coating, filling and fairing, bonding, laminating and much more.
WEST SYSTEM epoxy is ideal for use as a coating and will provide a very effective moisture barrier with good abrasion resistance. Coating your timber will elongate the life of the new timber and if sufficiently applied then it should last for many many years. WEST SYSTEM epoxy may be pigmented but there is little point to this as we recommend that you apply a non slip grip paint over the surface of the epoxy, which will provide the grip for you and also protect the epoxy against UV.
60 square feel = 5.6 square metres, therefore you will require 0.8kg for the first coat & 0.65kg per subsequent coat x 2. Total epoxy required for 3 coats is 2.1kg = 2 x A-Packs (1.2kg)