ORIGINAL: combatpigg
A lot of designs with the swoopy lines, rounded perifery, strakes, etc. aren't easy to measure and make me more skeptical about using an on-line computer instead of going with chalk lines on the workshop floor.
Good idea those chalk lines.
Good idea to measure them with your yardstick too, if your projection of them was accurate at all, that is. Good thing about the task is that you're looking for a starting location for a safe CG for the first flight. You don't need to follow the swoopy lines with the yardstick any closer than any other method needs to figure out what to draw for the swoopy lines and perifery on a piece of paper for the less comprehensive method.
You do bring up an excellent question about the "simpler" method of drawing a scale wing planform. How would figuring the location of the tip chord for that scale drawing differ from using a yardstick? Can you give us your method of guestimation used to come up with the lines to draw? I'm guessing it just might be about the same estimations anyone would make while trying to figure where to hold the yardstick. So there's less problem guessing what lines to chalk than where to hold the yardstick? Do the swoopy lines become straight when chalked?