I see lots of patterns that I want to make and am thinking that I could do quite a few without buying the actual pattern. Then I start thinking about the HST and am not sure the best way to start. I know about laying the two squares together, marking the line and then sewing on either side. It is the starting measurement that I am not sure about. Is it slightly bigger than what I want for a finished block? If I want a 4-1/2" HST block, are my starting squares 4-1/2", or bigger? Do you lose a bit because of the technique of sewing first then cutting?