Make sure you use Nitrile gloves and you work in well ventilated area when working with epoxy! Avoid any skin contact.
Rules of thumb
1) Use epoxy above 20 degrees C, minimum at room temperature!
2) For every 10 degrees you raise the temperature of your layup, the epoxy cure time will half. In general a full cure takes 7days or more. But in 24h typically you will have 90% or more of a cure. If you imagine that you cured at room temperature + 10 degrees C, the the same cure will be achieved in 12h. If you imagine you cured you layup at room temperature + 20 degrees C, the same cure would have been done in 6h. Many resins cure at 80 degrees C in just 30minutes or so. Further more when you cure at higher temperatures, your resin will be more viscous, and penetrate the composite fabric better, giving better result. Best to leave in press 24h. Heat slow and cool slow.
3) The stiffness of your final product, total thickness of your ski/snowboard, is proportional (^1) to the composite material weight/stifness, but to the third ^3 to the core thickness within the composite material! This means you can increase the stiffness/weight of you composite material to improve stiffness or you can increase the core thickness, however the core thickness is a much more effective way to do it.
4) Weigh your fabric first, then mix the same weight of Epoxy +10%. This is a good start to get optimum fabric/Epoxy ratio.