If you understand linking/unlinking, then do whatever you want. Creating a brand new player is the easiest way to avoid the issue if you still don't understand what linking means.
Just don't spread absolute bullshit on here that editing on-disc players provides a different result to using Create New Player. Editing on-disc players without understanding the implications is where problems arise.
One of these is your Guptill downloaded straight from the sever. The other one is a player I recreated using 'Create New Player' and uses the same sliders as your Guptill. They are the exact same thing (give or take where my slider setting isn't exactly the same as yours).
For those who want to create players and avoid any linking issues, just create a brand new player. It produces the same results as editing an existing on-disc player.