I would sand to 120, then wet the boat entirely to raise the grain and help heal staple holes. When thouroughly dry, sand with 180 and stain. The finer your sanding job, the less blotchy the stain will be so I don't think 180 or even 220 is unreasonable.
I'd be afraid to sand the seal coat at all, just a quick and light rub out with fine abrasive pad to knock off the nibs should do. Remove dust and glass away.
Just my opinion based on one unstained boat and 40 years of furniture making.
Ian

: I would like to stain my hull with a Solar-Lux dye and seal the
: Cedar with epoxy before glassing. I plan to sand to 120 grit and
: fill the staple holes using a hot iron and a wet towel. Then
: apply the dye and, after it dries, apply the epoxy seal coat. Is
: this a good plan? The best plan? Will I be able to lightly sand
: the seal coat smooth without hurting the dye?
: Thanks in advance,
: Randy