A little late, but sometimes putting the power tools aside can be easier. I've cut two sets of them with a hack saw in a bench vise. Takes some elbow grease, but really not that bad. Touched them up on the disk sander when done.
Yes, worry about it. You need to get them tightened as spec'd. I tried something similar to what you're describing without much luck either. Waited until the wheels/tires were on and sitting on the ground, the drive train installed and in gear, and the e-brake set. With all that, it was rock solid and I could put my weight on the bar to tighten. Achieved the 45 degrees without too much trouble.