Adjust column width of a table in R

Question

I have a table with 4 columns and I want to customize width of the columns such that the last 2 columns (day0 & day10) are narrower than the first two columns (Experiment & Lab).

mydata<-

    Experiment  Lab day0    day10
    experiment 1 condition2 Lab 1 location1 2   4
    experiment 1 condition3 Lab 1 location2 6   7
    experiment 1 condition4 Lab 1 location3 21  21
    experiment 1 condition5 Lab 1 location4 16  12
    experiment 1 condition6 Lab 1 location5 14  14
    experiment 1 condition7 Lab 1 location6 5   20
    experiment 2 condition2 Lab 2 location1 0   0
    experiment 2 condition3 Lab 2 location2 18  10
    experiment 2 condition4 Lab 2 location3 1   2
    experiment 2 condition5 Lab 2 location4 4   84
    experiment 2 condition6 Lab 2 location5 1   3
    experiment 2 condition7 Lab 2 location6 3   8
    experiment 3 condition3 Lab 3 location1 2   11
    experiment 3 condition4 Lab 3 location2 0   5
    experiment 3 condition5 Lab 3 location3 8   16
    experiment 3 condition6 Lab 3 location4 2   3

my code

formattable(mydata, list(`day0` = improvement_formatter)) %>%
  as.datatable(rownames = FALSE, escape = FALSE, options = list(columnDefs = list(list(className = 'dt-center', targets = c(2,3))),pageLength = 70, autoWidth = FALSE))