1/8" is too small to worry about. Some vehicles are not equal on both sides of the fenders. Ours is up to 1/4" out on one side but I ignore it. You must have equal chain links on each side. If you have a 4WD, it's going to be a little uneven because of the weight bias to one side from the transfer case, driveshaft,etc. I think some vehicles are just not made that accurately and you won't find the fender height is even side to side, front and back. Things like springs can sag a little with time. There's simply things that will cause uneven height side to side and you can't worry about it. If you haven't had a wheel alignment done for some time, that's a good thing to do.
If you could post a pic of your hitch, that would possibly help. Are you planning to raise the ball an inch? That will change the geometry a little and affect your setup. It's sounds like your bars at 6 and 6 are what you want to keep them horizontal, but if you haven't, raise the ball an inch and you will find that the head angle and number of chain links will likely change a bit. Chains commonly have 9 links, so at 6, you will have 3 links left over which is good. At 7, you'd have 2 links left over which says things aren't quite set up right.
What you want to do when setting up the ball height on the hitch head is have it 1 inch higher the coupler on the trailer when it is perfectly level (before hooking up). That allows for a bit of settlement in the rear of the TV so that the trailer should end up level.
You should see if your manufacturer for a towing guide and see if they say what the front fenders should settle to. Different makes are a little different. AFAIK, you should never end up lower than the unhitched height. There is a really good sticky in the towing section here and it talks about fender height before and after. It's probably the best write-up around.