There is a formula for determining how much tongue weight you should have based on the length and where the axle is located on the trailer. I would check with the trailer dealer to see what he recommends. Then using a scale, you can actually determine how much weight is on the tongue of the trailer. I usually like to have it just slightly heavier than perfectly level. I have never measured the tongue weight as I have described, but I have heard of dealers doing this when they set up a trailer and truck to show the novice owner. Too much on the truck is also not safe. It is something that you learn from experience, just like setting the brake system settings. Just make sure that you always have everything tied down well, because if the trailer ever goes wild, what is on it will be tossed off quickly if it isn't secure.