What I did with the buttons was essentially bypass the circuit boards where the pads would get pressed and connected the buttons to the main pcb. When doing this you need to connect diodes to each switch. The logitech wheel doesn't use a common ground and instead uses a small matrix of sorts to figure out what buttons are being pressed. If you are connecting to where the pads would press you don't need to add diodes as they are already on the pcb. If you look on the side where the button would press you will see little black components labelled D1, D2, D3 etc, those are the diodes. If you are having problems with random button presses a couple things I would really look at closely are:
1) Making sure that the button traces are all complete and none are broken.
2) If you soldered onto the pcb make sure that none of the solder accidently made a connection to the other half of the button. Make sure that you have continuity from the pcb to the actual switch (in other words make sure that the wires you soldered onto the pcb are good).
3) Check the diodes to make sure they are still good. To do this take a digital multimeter and put it in diode setting. Put the black lead onto the side that has the 2 solder points and the red on the side with one solder point, you should get no signal. Now reverse the leads and you should get signal (mine are around 530). Don't just check the one at the start button check the other ones as well.
Funny you should ask about my monitor because I just changed it around on Saturday (4 days ago). I was using a 27" dual resolution arcade monitor that had 15khz/24khz. I connected to that using soft15khz with a ati 3450 video card. On Saturday I installed a new monitor, it's a 27" 31khz arcade monitor. The reason I decided to swap the monitor out is so that I could buy a newer more powerful video card. Not a lot of new video cards are working with soft15khz yet and it's more of a pain then anything. I was having problems getting my model 3 games running at 60fps and with a more powerful video card I can get some of the newer pc games running a bit smoother and with higher detailed graphics.
As far as the feedback is concerned. Before you start setting up the amc go into logitech profiler (don't use windows device manager yet) go into Options>Global Device Settings and turn down "Spring Effect Strength" and "Centering Spring Strenth". These are the two settings that cause the "rattle". To test it out turn them both right off to 0% (you have to hit OK for the settings to take effect). Rattle dissapears. Now what you have to do is find out which percentage is a good point for your exact setup (the potentiometers on the amc will effect this, you will need some trial and error). I have both of mine default at 12%, may be a good starting point for you. This gives me a bit of room to move it up or down depending on which game I'm playing. When I was testing each game has a different point that the "rattle" will start at and I set up a new profile for each game. I was able to succesfuly remove the rattle while maintaining a good feeling centering feedback in each game using either logitech profiler or emulator settings or a combination of both.
My pots are:
#1 Loop gain - All the way counter clockwise
#2 Current Limit - Is 6 turns clockwise
#3 Reference In gain - Before you adjust this unplug the wheel from the computer and then plug it back in (again just make sure you don't open the windows controller options - where you can test the different ffb effects, some weird stuff happens when you go in there and it seems to hold those weird parameters until you use the wheel for a different game or unplug it). Put a voltmeter on the Motor outputs 1 and 2 from the amc. You should be able to turn the wheel all the way to the left or right and have the voltmeter read +24V or -24V depending on which side you turn the wheel. If its over or under then adjust the reference in pot until it reads 24V at full lock. If its slightly higher on one side then the other adjust pot #4
#4 Offset - Put a voltmeter on Motor outputs 1 and 2 from the amc (motor + and motor -) adjust this pot until the voltmeter reads 0, or very close to 0 when the wheel is at center.
The windows game controller page is bad. From what I can gather it basically works as its own game and loads up its own "profile" to the wheel. Basically however the wheel reacts in that means nothing. It has its own individual settings for ffb just like every other game has its own ffb settings. It can really screw things up when you are trying to trouble shoot the ffb effects in game and then switching and adjusting things in windows game controller menu. I spent many a hour messing around with that before I realized what a piece of crap it was and how badly it was screwing up my trouble shooting. I'd say just skip it entirely, and load up the game you want and start adjusting each game until it feels good using the emulator ini files and creating profiles in logitechs program.