Tractors

I purchased a Poulan XT Yard Tractor, and I have question concerning transmission/clutching/breaking. When I depress the breaking pedel and release it to engage the transmission, there is an extremely small area where the transmission completely engages. The breaking lever/pedal has a lot of play then the transmission engages quickly, There is virtually no play between engaged and not engaged. At high gears and high speed the tractor wheelies. Now I can with great patience slowly engage, but one little slip and wheelie time. Now if I reduce the speed, the jerk is not as bad. When you are mowing, the manual says keep the grass cutting blades at a fast speed. I feel when operating the tractor, one should be able to break or slow down gradually and excell gradually when operating the brake lever. This is something you do often when cutting around trees and awkward areas. Its not feasable to come to a complete stop change gears and than go. I have owned other tractors, and their clutching system had a smooth transition. I explained the problem to Home Depot and they let me drive another one and it was better, but not as nice as I would like it. I traded because that one was better than the one I had. Is there a way to adjust the clutching system to create a gradule exchange from stop to go, or from slow to fast? I'm a grown man who have used yard tractors for years and I feel the adjustment is wrong. If this was a person's first tractor, or was more frail, or apprehensive they would not be able to control it. The tractor would most likely be returned. Any Suggestions/recommendations? Thanks Michael Dorsey, mmdorsey@cox.net