The unity mod is fairly straight forward. Unsolder the output jacks, and cut off the ``tip`` solder pin. With a Dremel you may want to even grind back the remaining pin, this will ensure that it doesn`t dig into the insulation of the wire you`re going to install next. Now solder one wire into the hole where the pin was, and another wire onto the metal tang above where the pin was on the jack. These two wires will run to your pot, the board wire to the 2 lug, the jack wire to the 3 lug. Ground the 1 lug. Repeat the exercise for the other output. You could use individual pots for right and left, or like I did, use a dual pot.
For the Whammy, if your version has no 27C256 chip, that means that the code is stored on another chip on the board. This is fine, since it involves much less work to convert. Solder in new sockets for the memory (you`ll need all four for the SS), and a socket for the 27C256. You`ll also need some 10uF Tantalum caps, and an MC34064. Once all you memory, caps, MC34064, and programmed chip in installed, you can install the switch. The switch can be a SPDT, or DPDT if you want to add indicator LED`s. The switch has a resistor on the common pole (check the value here in the thread, the value escapes me at the moment), and will either give +5v or ground on boot up. Depending which, it will boot the unit into Whammy, or SS mode. Check my Whammy pictures, you`ll see that there are through holes on the board already that you can use to solder in your wires. This is much neater and more secure than soldering onto the components. If you look at the picture of the switch, you`ll see that I soldered the resistor directly to the center pole, and then covered it up with heatshrink. I THINK that the resistor is 100 ohms, but like I said, double check the thread to be sure.
As for true bypass, that might be tough. I don`t think that there is enough room underneath for a switch. Check it out. Personally, I don`t have a problem with the bypass on mine.
Cheers,
Dino