I would always run a ladder with different bullets even if very similar. IMHO. It's quick, easy and why not. You could then go up the the 4.3 grs. you are considering.
One thing to consider when changing bullets is the seating depth, which is not the same as OAL. If the bullets are different lengths then the heel of the bullet of the longer one will be further in the case, which means a smaller combustion area and, probably, higher pressures.