......... I have screenset 2010
so I did not have MDI
sorry
In the 2010 Screenset, you can use the MDI at any time. Just hit the ENTER key to open the MDI, type your feedrate (F50 for example) and then hit ENTER again.
What you might want to do is add your feedrate (F###) to the Initialization string in General Config. Then, when you first click RESET, it will set your feedrate to whatever you put in the Initialization string.
Mach3 defaults to 6 units per minute, if you don't do one of the above things to change it when it starts.
If Mach3 is in Continuous Jog mode when you close it, it should remain in Continuous mode when it restarts.