One thing you might try is to do your drawing at a larger, more comfortable scale. Then if you scan it, you can scale it down to actual size digitally using Photoshop, Illustrator, gimp, Autodesk Sketchbook or probably even Paint... any software that you're used to, and print it at the correct size. Or you can do it old school and use a photocopier that has a reducing function.
Looks great!