I am finishing up my first stripper canoe as practice before I build a sea kayak. One problem that I have is that there is un-eveness in the hull (bumps and valleys), this is after sanding. My question is, How deep can I go with using epoxy and cabosil mixture to fill the valleys? I don't want to keep sanding as I am getting thin in some areas. I am using RAKA with the non-blushing mix. Thanks in advance for the help.