Your questions are very subject specific and not closely related to R or R studio. I would assume that many of the people in this forum have no experience in analysing eye scanning patterns, I for myself have no idea what "human RT" refers to. Thus, I think it is rather unlikely that you'll get a meaningful answer in this forum.
If you'd describe your data and your aims more thoroughly, someone experienced with statistics and data analysis might be able to give you some hints, but that would probably still be on a rather general level.
I would advice you to find a platform where you can discuss your questions with people that are experienced in the field of research that you are involved in. I also think it is very valuable to read the method sections of scientific publications that describe experimental setups that are comparable to my own work . By that, you can get insights in how others have analysed data that is similar to yours and some inspirations in how you can analyse and present your own data.
If you then need support during the implementation of your analysis in R, this forum is of course a very good place to get this support.
I am sorry that I cannot give you a more direct answer, but as I said, I have absolutely no experience that would qualify me to tell you anything else.