Tongue weight help

I thought I followed the directions from GMC. I weighed the truck/trailer combination first. I kept the weight bars attached to the brackets on the frame of the trailer. It is a Husky Centerline hitch with 800-1200 bars. Pulled off scale and unhitched and also removed the hitch and got the second weighing of the truck alone. We tried to load the trailer exactly with the items we will be taking on our next trip as well as all cargo including full tank of gas. Occupants and dog stayed in truck during both scale uses. Placard on trailer says 6455 dry weight, 1,112 lbs cargo weight, gvwr 7,605lbs, gawr of front axle 3,500 , gawr of rear axle 3,500lbs. Its a 32 ft trailer. Truck is a 5.3 shortbox crew cab 4x4 with a gvwr of 7000. 3,42 axle ratio. Yes a 3/4 ton truck probably would have been much better, but this is the one we have for the next few years to work with so I need to make it work. We have pulled the camper several times and I feel the truck pulls it ok, but passing semis on interstates going 70 while we're doing 60 pushes us frequently. Somtimes passing suv's do as well and I dont like the feel ofsome loss of steering. From the beginning, to me the truck feels light on the front end, although I have not encountered problems to curves or turns. Dips in the pavement can give a bucking ride sometimes. I mainly want to feel more weight on the front end. We left the hitch setup as was done at the trailer dealer where we purchased the trailer and hitch. Before taking the rig to the scales, we measured distances from the top of the wheel wells to the ground which was pretty level. Unhitched the truck and front wheelwell measured 36 1/2 inches, rear wheelwell was 37 1/2 inches. Hitched up trailer without using the bars and front was 37 3/4 inches and rear 35 1/2 inches. Then hooked up the bars to trailer bracket and front was at 36 3/4 inches and rear was 35 3/4 inches. I can raise the bracket higher to move some weight off the rear tires, but am half afraid to try as pulling a trailer is new to us. Hate to drive the whole thing back to have dealer just raise the bracket if that is all I need, but again I'm hesitant to pull it out on the roads for fear of I might make it a wild ride if I am wrong. never towing before makes it hard for me to judge if that front end feeling is normal or not. I was shooting for tongue weight of 12% (859lbs) and if I am at 640lbs I'm not even at 10% if I calculated the trailer weight correctly.