My husband and I have finished putting down our hardwoods and sanding them. After we stain and polyurethane do we sand again before the second coat of poly? Also what kind of sander do we use and what grit? We originally sanded with a large belt sander that we rented but the highest grit we could get was a 100. There is a sander we can get from lowes but it's an orbital sander and I'm worried about it leaving swirl marks on my floor. I would also like to know what kind of poly would be very durable without it being very glossy. Any advice is appreciated!!