I typically use System 3 Silvertip epoxy. Especially when the temperature is down I find it a little hard to get it to lie down for final flow coat. In contrast, Fiberlay epoxy is much thinner and will lie flat for the flowcoat.  One could use both types or thin the thick epoxy.  Kern at Sys 3 tells me that the Silvertip can be thinned up to 20% with lacquer thinner.  Provided the surface is not porous.

I have not tried to, but I wonder if the much thinner Fiberlay epoxy might flow out from the near vertical surfaces of a CM bagging?  Solution to that would be adding cabosil.  Or use the other epoxy.