Who did the tras? Was it a custom build, or a stock rebuild? When upping the line pressure, if you go to far (without the resistor installed), the trans will go into limp mode. The different seperator plates, springs, orfices and what not make a difference.
How firm the shifts are, isn't all in the pressure. How the VB is otherwise setup has an effect as well. IIRC, mine is up ~180psi on the top-end. The way Dave sets up his VB, all depends on what you are plannig to do with the truck, and how it is used.
Since the PCM "learns" how you drive, it will firm up the shifts if you tow or drive with a heavy foot. If you drive with a somewhat light foot, or not towing, it will soften them up. Makes a difference if you manually shift the trans as well. The more you do, the firmer they are.