Great questions. I am in the process of doing a video on wheels differences with the guys at AMV. I will make sure these specific topics are answered in the video.
Here are the short answers. These are based on the information that I have received. As a disclaimer, I am not an engineer and I have not yet tested the different wheels first hand. I was hoping to do a vlog of track testing to provide some real-world information but Covid-19 has put that on hold.
-67mm v. 58mm PCD: I have been told there is no appreciable difference. Some kart manufacturers use the different bolt pattern so that is why AMV makes the different versions. You are not the first 175cc shifter pilot to ask this question
offset: a more inward offset provides more grip during the acceleration phase (center-off) of the corner. AMV state that the Tiger which has a more inward offset (63mm v. 58mm) and a longer 3 spoke design is more rigid.
wheel recommendations for shifter category: AMV recommend the Tiger as the starting point for shifter karts; for TAG the starting point is 3F. Matt Hamilton won G1 at the 2019 SuperNats with Tigers. Race Liberante ran both Tigers and 9Fs at the SuperNats. He had his fastest times on the Tigers and won the P2 final on 9Fs. I am in no way trying to suggest that Race or Matt won the SuperNats because of AMV wheels but simply they were one part of the overall puzzle. I don’t know Matt but I know Race liked the way 9Fs felt - he said he felt very confident on them.
The graphic uses TAG / OK karts as the starting point. For shifter karts, the ideal starting points move to the left a bit. Each wheel has a large performance envelope so don’t think of the wheels as discrete points but rather overlapping performance envelopes.
I hope that helps.