I've been using a LEE Auto prime II for years now and prime pistol brass on the Dillon 550.
I just recently acquired an RCBS Bench Mounted Priming Tool, and it is great. I have some older CCI Large Pistol primers that I traded some shotgun primers for and the Lee nor the Dillon would seat them, but the RCBS no problem.
Not being a precision rifle shooter, it would seem to be that seating the primer completely would be more important than any particular measurement.
I personally see no reason for me to have the Holland upgrade although it looks like a good option.
I just recently acquired an RCBS Bench Mounted Priming Tool, and it is great. I have some older CCI Large Pistol primers that I traded some shotgun primers for and the Lee nor the Dillon would seat them, but the RCBS no problem.
Not being a precision rifle shooter, it would seem to be that seating the primer completely would be more important than any particular measurement.
I personally see no reason for me to have the Holland upgrade although it looks like a good option.