I have the opposite problem. I tried making a solo seat for my CB450 and did a great job on the cover but totally fooked up on the foam contour and overall seat size. It blends nicely into the tank and looks cool in sort of an old trials bike way (if you can imagine "CB450" and "old trials bike" in the same line of thought) but it's sort of like sitting on a fabric-covered cannonball.
But you could bounce a quarter off that taut, wrinkle-free seatcover. Maybe I just got lucky that one time. I need to go back to the drawing board.
I agree that your $20 was well spent. When I had my Z50A-K2 seat recovered years ago I took the pan and foam to a local upholsterer and asked to have it covered in some sort of snowmobile-type cold-crack resistant material, and they did a great job but it cost about $75. Still, it's held up well, so I feel okay about that. I'll be interested to see what having the seat for my son's bike recovered locally costs now, 15 years later.