Which rear u-bolts are you using? If they're standard 1/2", then the standard 65-75 lbs will work. But if you're using an up-rated 9/16" or 5/8" u-bolt, then the torque levels are much higher.
And tight or not, you still need to address the parallelism of the two links up front. Nothing is ever going to be perfect until that is done. Look at CharlesWhite's pic and you'll see a much more consistent driving setup.
Even though his does not look perfectly parallel, it actually is much closer than it looks because the draglink has that slight kink at the lower end. We use the term "parallel" to describe what we mean, but in reality what is at play here is that the two pivot points need to be working from the same level distance from one another.
In the case of two perfectly straight bars then, they would be parallel.
He's actually got the dropped pitman arm I was mentioning before (maybe it was in a PM?) that has less drop than the typical EB arm. If you look at these pics:
http://www.wildhorses4x4.com/category/s?keyword=pitman+arm you can see the difference in the amount of drop between the #1275 and #1286 for the EB's, and the #791275 for the full-size trucks.
If you end up only changing the pitman arm, this would be the way to go for height, but you'd need to shim the larger tapered hole, or get a custom upper link.
The easiest way is to replace both the arm and the drop bracket with a semi-matched set.
As you're finding out, on lifted Broncos it's a good idea to get all the goodies to correct for steering and suspension locating.
Those would ultimately be:
1. Dropped pitman arm.
2. Dropped trackbar bracket.
3. Adjustable trackbar.
4. Adjustable draglink.
These all work in concert to lower the overall angles of the bars, ensure that your axle is centered in the frame, keep the bars as parallel as possible, and finally allow you to keep your steering gear box in it's perfectly on-center position for best road manners.
Paul