Welcome to the site! However, your question is not clear to me.
Are you talking about adjustments Bill does in his tunes or are you talking about things you can do to change "firmness"?
When Bill sets up your tunes, he modifies three things:
1. Ford's "Torque Reduction" strategy that is used during shifts.
2. Line pressure.
3. The interval between the point at which the clutch bands release and re-lock during the shift.
The result is, of course, a shift that is both "kind" on the transmission and one that doesn't "drag out" leaving you wondering if it's ever going to happen.
If you have made any changes to your transmission, such as "shift kits", you MUST tell Bill what you have done when you order your tunes. There is a place in the order form for this information.
Now, if you're talking about the "User Adjustments" that are commonly called "Firmess" that you can do (once you have the programmer), the only thing YOU can modify is the delay between clutch band release and lockup (a millisecond value). If you increase the delay, it draws out the shift and puts more "slip" on the bands, leading to increased wear. If you decrease the delay, the new gears engage quicker, but if it's too quick you put great stress on the mechanicals in the powertrain (things that are spinning must suddenly change speed). So, you really should not make big changes to the settings Bill has put in your tune (unless you know what you're doing and think you are a better tuner than Bill).
That said, there are always people who think they "know better". I always advise them that you want a "quick lockup", but, as another Mod, Longshot270, has said, "You don't want the shift to feel like a kid is in back kicking your seat back."
I left my shift firmness alone - exactly the way Bill set it up.
- Jack