9.2 screens. One screen is:
*** Spoiler - click to reveal *** basically the maximum amount you can draw before Q tells you to retry because you drew too much. There are about 13.5 lines to a screen, a line being one complete draw from side to side) This is approximate as best I could figure out.
10 Tonnes worth of lines--this one has me puzzled how it remotely fits with 9.2 screens, unless my math was way off, and it's actually 10 screens.. or some other weird math. 10 Tonnes worth of lines could equal 10,000 Kg, but that doesn't quite fit.. Either way, this will probably easily be one of your first 5-7 achievements!
If you want the fastest way to boost the drawing achievements USE YOUR KINECT. *** Spoiler - click to reveal ***Load up the draw test screen, then just spam one continuous shape all over the screen until you get the "retry, too much drawing" warning. Press to do it again... etc. I recommend backing out to the menu once in a while just to watch the progress in the achievements and make sure it actually saves! UPDATE: Great tip from FleqxMLG, hold the left trigger while drawing and it goes much faster! Instead of 45 seconds with the controller on slow speed, you can do each full screen in about 15 seconds or less! With the Kinect, I was able to do each screen in circles in about 10-12 seconds. Definitely KINECT if you can!
I went through just to find out how much drawing is required for each of these as the last few are very grindy.
If you would like to see the full list of drawing achievements:
*** Spoiler - click to reveal ***
(please note that these are approximated as best as I could)
1/2 screen=20,000 sushi in weight
3.5 screens=2 Tatami mats in area
9.2 screens=10 Tonnes worth of lines
13 screens=One African Elephant in weight
17 screens=Sagrada Familia's 1/10th height
32 screens=The circumference of Stonehenge
50 screens=300 Sumo wrestler's weight
63 screens=Sky Tree's 1/10th height
92 screens=777,777 hamburgers in weight
139 screens=The Giza Pyramid's height
181 screens=A Blue Whale's weight
380 screens=Mt. Fuji's height
500 screens=The Iguaza Fall's width
650 screens=30 Moai Statues in weight
750 screens=Notre Dame in area
900 screens=Mt. Everest in height