Well, Kiwi, now you're in for the hard part of falling.
As far as wedges go Stihl wedges are as good as any. They seems to have the right mixture of hardness and toughness. Some wedges are too soft and when in a hard wedging situation tend to heat up and are very easy to take chunks out of. If you hit a Stihl wedge and aren't square on the head you can break them, especially if it's real cold out.
I use 12" wedges exclusively. If you take a look at the pics I've sent you can see that not all of my wedges are a full 12". The ones that are "used" a little I tend to use the most. In other words, the shortest wedge is the wedge that I'll put in the tree first. It's generally a little thicker as I've tended over the years to hit it with the chains taking off the fine edge. Now since it's shorter I use it first as it won't have that tendency to get hit by the chain as it's already thicker and makes contact with the wood sooner thereby giving me almost immediate lifting capacity. If I were to use the shorter smaller wedges they would sink in quicker and further and not give me that immediate lift. You have to take care of your wedges just like every other tool you use in the woods. As you can see by my pics my wedges are in good shape, even the shorter ones. I use a horseshoe rasp to make sure the recieving end of the wedge is square so I have a solid surface to hit. The 12" wedge also offers a larger target to hit with an axe.
Where you place your wedges in the tree is also going to make a big difference on how your job turns out. It can make the difference of losing a little bit of water to sweating a gallon. When your going to have to wedge a tree over it's lean, always place the wedges directly behind the undercut. This shocks the tree directly over the undercut. If you place them on one side or the other you're wedging against the hinge wood. When placing your wedges and have to use two of them, place them together. I see men place their wedges 12-18" apart in the backcut. This does no good and makes them have to move every time they're hitting the wedges. If you place them together your using more surface area and in the case of a heavy backleaner they don't have the tendency to cut into the wood as much. This also allows the wedger to stand in one spot and alternate one wedge and then the other. This is typically know as "walking" the tree over. Hit one wedge, give it a second for the top to move forward, and then hit the other wedge. If you wedge too fast your wedging against yourself by hitting the wedge when the top of the tree is moving back from the hitting of the first wedge.
I'll use my shorter wedges first to "set" the tree to keep it from sitting back on the stump. This allows me to use my "good" wedges for the tougher wedging later on. Look at the pics and you can see what I mean by shorter wedges.
If you use the smaller wedges they have a tendency on larger trees that have a heavy backlean to cut into the tree, thereby losing effectiveness. This is especially true on softwoods. The 12" wedges also have more lifting surface as far as width.
One of the most important items that you need to keep on hand is a decent falling axe. I've enclosed a few pics of my favorite axes accumulated over the years. At this point I use nothing less than a 5 lb axe and am very picky about the head. In the pics you'll notice the different heads. The one thing that each of these heads has in common is the striking surface. You'll notice that each one of them has a nice, square head with no sharp corners at all. Sharp corners are the nemesis of good wedges. You'll also notice that my axe handles are 36". You can use shorter handles and smaller heads but if you're in a real wedging situation that needs your attention the heavier head with longer handle properly used will save you a lot of sweat.
Well, as you might have guessed I could go on and on with this thread. You'll get a lot of good advice from some very good fallers on this site. Keep in mind I'm from SW Washington state in the Pacific NW. I'm used to falling softwood with the exception of maple and alder so pay attention to the type of wood you're cutting. This will make a difference in your wedging also. Hope this helps a bit.
I guess the pic of the 36" handles didn't upload. Too much info.