Re-Aligning the X/Z axis after replacing bearings in my Wanhao i3?

I have an older near-Version 1 model Wanhao i3.

I had a hell of a time attempting to reach the set-screws to remove the x-axis rods so I could replace the bearings on my printer. I was eventually forced to completely take off the entire assembly to get at the screws.... i pretty much removed anything on the Z-axis except for the threaded rods attached to the steppers.... but now that I did that, I realized that I have no idea how to make sure that everything is completely parallel and the correct length from each other.

First thing I am trying to ensure is that the two parts that go along each side of the z-axis rods are are exactly straight across from each other and not at a slight angle/diagonal from each other. Can anyone suggest what would be the best way to try to verify this? I don't mean their heights from each other, as that can be fixed by hand by moving just one side and there was a blueprinting video on that, I meant that neither of them is at a slight diagonal from the other and both of them are straight across from each other in terms of any tilt across the Z-Axis.

Also, how can I make sure that they aren't too close or too far from each other? I had an issue putting the entire assembly back on the rods due to them not being aligned exactly at first, and had to resort to putting the two black boxes that hold the rods on each z-axis rod first, and then putting the x-axis rods in at different heights.... but I still need to take off this entire assembly to get at the set screws yet again to tighten them. (Can I just use normal screws in their place? The set screws are a %^$&#$%^#%$ to work with with the limited space you have for the top x-axis rod). I am worried about them not being the proper distance from each other and that causing issues or even grinding against the z-axis rods.

Also, is there any difference between the top and bottom X-Axis rods? Or are they both just the same rods and it does not matter which one goes where?

Finally, I was very careful while working with it, but I did still need to basically take off every rod and put it back while doing this, and trying to get it to fit at first, so how easy are these rods to bend? I doubt I bent any but I wanted to know if this is something so easy to do that I could have carelessly done it without even noticing.