It sounds like you are using a single platform scale. In order to know the tongue weight you must disconnect and weigh the truck separately. You cannot calculate load transfer unless you weigh with WD and then weigh without. In order to get all the information you need you will have to weigh multiple times. If you are using a single platform scale it takes a lot more effort.
First before you go, make sure you are hitched correctly, your trailer is setting level when you are hooked up. If it is not fairly level one trailer axle carries more load than the other.
I went to a Cat Scale, with truck and trailer loaded to go camping. Their scale has three platforms built into one scale: truck front axle, truck rear axle, trailer axles.
Using the directions shown here http://catscale.com/how-to-weigh
, I placed the truck steering axle on front scale, truck drive axle on the middle scale, and the trailer axles on the rear scale.
1st - weigh loaded truck and trailer with everything hooked up and weight distribution tensioned.
2nd - weigh loaded truck and trailer with everything hooked up and weight distribution NOT tensioned.
3rd - park the trailer somewhere and weigh the truck only.
I use these to calculate the various loads/weights.
If you do not get correct weight distribution on the first weigh, you may need to adjust the hitch per manufacturer's instructions and re-weigh. (repeat 1st step till you get load transfer adjusted correctly)
Cat Scale operators in my area charge $10 for the
first weigh and $2 for each additional weigh while you are there. It takes me about half hour for three weighs, since the scale master required me to get off of the scale between each weigh, he said to re-calibrate between each.
In addition to this, some people suggest weighing each wheel separately to make sure an individual tire is not overloaded, but I have never felt the need to do that on the trailers I have owned. I do not know where scales are available to do this.