More coats the better. I typically lay down no less than 8 coats and usually 10 coats before I start my fine sanding...I also use the epoxy to fill grain, so if yours is that far, you may be able to skip a few coats.
I just hate the thought of sanding through the finish and having to start all over.
I also wouldn't go below 800g unless you have to.
I start at 1000 unless I have to fix some spots and then 1200, 1500 and then 2000...all of these wet.
Then I machine buff starting with a polishing compound and progressing threw two finer polishing compounds followed by hand buffing as necessary.
Have fun, bigjim