Actually, rounding after you seal doesn't work because there is just too much bunched up plastic. I start with an 11" vac bag, sealed on one end for my 7-1/2" wheels. Before I put the cheese in, I use a 9-1/2" plastic lid as a template to draw a circle on the bag. I do multiple seals along the drawing line to make a sealed circle on 3 sides. You have to insert the cheese wheel before you start sealing up the open end. Then I seal up about 1/2 of the remaining open end. You have to leave a pretty good sized opening for the FoodSaver to draw a vacuum. After I vacuum, I finish sealing the open end as close as possible to the cheese.
This makes a really nice presentation but is a pain in the butt if you do it with the FoodSaver. THAT'S why I bought the 12" impulse sealer. I should have it in the next day or so, and will post pictures of my technique.