Matt, I use a scale of 3/4" = 1 foot. Then, 1/16" = 1". When drawing a 90 degree curve, say 30" radius, I simply measure 30/16" (1 7/8) from the end of the tangent line, make a dot there, then measure 1 7/8 again, at a right angle to the tangent line, and mark that. I just draw in a rough curve to connect the tangent to the second mark. I'm not one for exact scale drawings, they aren't needed. I allow 1 foot (3/4") for each turnout. This method will accurately let you know what will fit. It suffices in most cases. If you are trying to cram a lot of track in a little space, then a more to scale drawing should be made.
Gary