The new Mach4 Mill wizard runs as a standalone program. You can open it in one window while Mach3 is open in another window. You can use the wizard to generate code, save it to a file, then switch to the mach3 window and load the file. The Mill wizard will remain open and you can simply click its window and run again. This can work for any function, and you could even have a more complicated job with multiple operations, then just edit one operation and click save again.
To be clear there are 3 sets of wizards:
for mach3 there are some free, user submitted wizards, of which Write is one, which are not supported.
There is the Newfangled Addons for Mill for mach3 which are extra cost, and are supported.
Now there is the new Mill Wizard for Mach4, which costs $75, runs as a standalone program, and is supported.