Doesn't matter what the trailers GVWR is or it's dry tongue weight. What matters is what the tongue weight is when the trailer is loaded for a trip. So you would need to load it like you would for a trip then check the tongue weight. I always say 12% is what you want to be at. Is that 400lb tongue weight loaded for a trip or is it when it's empty? Either way you need to load it and then weigh the tongue. Get a Sureline tongue scale and then you can move stuff around in the trailer as needed, after you weigh the entire trailer.