...I thought I could help you on this...but maybe not. It's been so long since my painting career I can't remember about paint adhereing to varnish. Paint does not really have good "tooth"...doesn't stick well to most surfaces. Primer is formulated in such a way that it will stick well to surfaces...And paint will stick to it....but of course primer doesn't really cover, or lay well. Paint does. Paint will also adhere very well to sanded epoxy. Just not sure about the varnish. Seems like I should be able to remember...but can't. Since you have only one coat of sanded varnish I would think that you could probably heavily resand, apply the paint, let dry completely, then continue varnishing.