is there a better way of modeling cylinder with a flat end???

i modeled a cylinder with a flat end, but i'm not completely satisfied with the end result. i surfaced a cylinder, then the flat part and lofted between the two (i've included the model). i don't know the width of the flat part based on the diameter of the cylinder and the amout of deformation there is between the flat part and the cylinder. i'm curious if there's a way to take a cylinder and actually "flatten" the end, using the deform, indent, or freeform tools, or any others, to get a more exact result based on the diameter of the cylinder.