I think Tengen Toppa Gurren Lagann actually did perform a Giga Drill Break in the movie. In the movie where Super Granzeboma broke the drills of all the Gurren Lagann forms, it was left somewhat clear that they actually were Giga Drills. It is indicated through Super Galaxy Gurren Lagann, when it was its turn to hold off SG. It used a drill made from both of the Giga Drills on its shoulders, which as we know is how it does the Super Galaxy Giga Drill Break. The size that was displayed could also be wrong, since in the TV series where Granzeboma was breaking Gurren Lagann to its preceding forms, the mechs were displayed with disproportionate size. I think, Gainax just wanted to display the mechs, at that moment. If they used the drill's actual size, no one would be able to see the mechs. Remember Tengen Toppa, Arc, and base have the same drill color and design, so it would've been kind of boring if Gainax didn't display the mechs to show distinct differences. Anyway, I could be wrong at the same time, I'm not 100% sure, but my reasoning should be good enough to take into consideration.