Hi. I have Glidecam HD 4000 and I use my canon 5dm2 and T3i. I did a lot of trial and error too but i tell you what my experience in balancing was.
Since you are using T3i with a kit lens (i assume the 18-55mm?) put just one counterweight on each side of the base.
Try to get the center of gravity of your assembly. REMEMBER to turn your camera on with the kit lens in whatever focal length you wanna use. set as if you are ready to shoot because any slight change that you do will mess up your previous balancing set up. put your center of gravity on the center of the mounting plate of the glidecam. whether you are using a QR adapter or the glidecam mounting plate itself, try to position your camera center of gravity to the center of the plate.
Position your glidecam from flat surface before you lift it for balance (Flat surface is important).
Try to rough align the left-righ/front-back alignment of the glidecam center shaft. Just align it roughly you can fine tune the balancing later.
The next crucial test is the TIMING. Position the glidecam center shaft horizontally and the time it takes for the base plate to travel 90 degress to bottom should be 2-2.5 seconds. I prefer 2.5 seconds when ever i set up. it's more stable for me.
In the event that your camera is heavier than the base. Try not to put counterweight right away (because I tell you they are damn heavy once you are gliding). Try to extend the center shaft first, make it longer, until you achieve the 2.5 seconds drop. But if the center shaft would be so long, then maybe better to add counterweight. But with you using T3i and a lens kit, I doubt you would use another set of counterweights. Just try to extend the shaft.
Once you get the proper timing, you proceed to finetuning your left-right/front-back balance.
Once you balance your set up, PRACTICE! it took me a lot of effort to practice and still i haven't perfected it like the way Devin glides his. That is the hardest part and where your sklills take over.
On your movement, try to do duck walk and try to tuck your holding arm near your body. what i do is that my other arm guides the center shaft so i can make tilting and panning shots.
Hope this helps. I am still learning till now. If you find a better trick please tell me
Cheers!