From my experience epoxy doesn't level out when applied to surface. This means a lot of sanding to get a very smooth finish. Sometimes another coat will need to be applied to achieve a smooth surface. Whatever your epoxy surface looks like after sanding is what you'll be living with. Varnish doesn't hide anything. Epoxy keeps curing and shrinking for months after being applied. If you want a perfect finish you might want to wait a couple months before your final sanding.