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For polar alignment, remember that even an approximate alignment is good enough for most wide angle photography if you are staying with a 24mm or wider lens, and 5 minute or less exposures. I often just align the altitude with setting the angle for your latitude on the altitude scale, and then leveling the base. Using a leveling base on your tripod is an ideal way to level the tracker, but you also can get a level plate with a bubble level that mounts under the tracker base to use as a good indicator, and then just use the tripod legs to adjust for level. For setting the azimuth, you can use a compass. Do not bother with the useless compass on the tracker, but rather use an external compass, and use the straight edge of tilt area of the tracker as a reference. There is some steel in the tracker that will affect the compass, so use some cardboard or plastic that has square corners on it to keep the compass 6 or more inches away, but still aligned. Watch out for any other magnetic objects nearby, that might mess up the compass, including nearby cars if you are shooting near to any. And be sure to adjust your compass to properly allow for your local magnetic deviation.
If you do want to use a more accurate polar alignment, the above approximate alignment is a great starting point. It is often hard to use the polar scope and get Polaris situated in the view of the scope, and this should usually get it in the field of view. For wide shots like with your 14mm lens, approximate alignment is usually fine. Just check your first long exposure by magnifying the image and seeing if you have noticeable star elongation. Be sure to check several areas of the image, because the amount of elongation depends on what direction you are pointed. For longer focal length shots, alignment obviously becomes more important.
I am not sure how tightly lasers are regulated over your way, but I have adapted a green laser pointer intended for astro uses to work in the larger hole where the polar scope normally mounts. The beam from that pointed to Polaris can give a very fast approximate polar alignment if it is dark enough to see the beam well. Keep your laser pointer warm between uses, because green lasers fade away as they get cold.
For the pivot base, I adjusted the washers under the little screw until I got a smooth rotation with no significant wobble. Then tightening the locking screw makes it all work fine. I used special small shim washers, but you can also do it by adding layers of thin tape to the face of one of the washers. If one washer is too much for your tracker, find a thinner one somewhere, and then shim it with layers of thin tape as needed.
For the locking screw of the base, I did replace it with a larger diameter knob with the right metric threads but that was tricky to find. You likely should be fine with the original knob there, but if you want to get something, look for a major parts supplier that might stock that kind of thing. For those in the US, or if you want to try ordering from here, a company called McMaster-Carr is where I get all that kind of weird or unusual mechanical stuff. The thumb screw knob for the locking base that I used was stainless, and needs to have a shaft projecting around 20 mm, with 5mm metric threads.
For the equatorial axis attachment of the plate on to the steel rotation hub, I would for sure not try to put a flat on it. The location you need to use will slowly change all the way around as you continue to use your tracker, and you want to be able to reposition the plate to get your ball head in to the right location. I did eventually replace my smaller locking knobs with larger diameter ones, but was working OK even before I did that. Mount your ball head on the tracker plate and then when you are ready to use things, put the plate and ball head oriented so that the ball head slot is kind of pointing upward. Then with your camera on, you should be able to aim your camera to what you want, but as you do, keep the camera kind of centered above the plate as best as you can by repositioning the plate. Ideally, your camera kind of is in balance at that location, and you need almost no clamping from the two screws. After you shoot a sequence, or when you re aim to a new subject, reposition the ball head and or the plate to keep the camera on the top near balance. That should allow you to work fine with the two locking screws that come with the tracker plate. If you do want to replace the two thumb screws, they need about 12mm of thread length projecting, and have 4mm metric threads. The knob size I used was about 16mm diameter, which still cleared the body of the tracker OK.
Slight wobbles at the rotation basewill not normally be an issue. The combination of the tracker and the camera end up being off center a bit in one direction or the other, and the tracking rotation will not typically rotate the load through the balance point during any given exposure. So the total load will tip one way, and be supported well enough to give a sharp tracked image. If you have significant wind that could be a problem, but your whole tripod is likely not rigid enough for wind issues anyway. And obviously, you need to be using a remote release for the camera, and not be touching it in any way at the start of the exposure or during.
I hope you have great success with the iOptron tracker. I sure do like mine a lot.
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