This would just mean you would have to run a very large number of requests, and take an average of them. That might be trickier, but if you can persuade a page

This would just mean you would have to run a very large number of requests, and take an average of them. That might be trickier, but if you can persuade a page to auto-reload it sounds quite possible. Another option, a little trickier, is that you could take user-definable values (like cookies) and not compress them. I haven't looked carefully at DEFLATE, but in many other compression systems you can choose to simply not compress a short part of the stream. This could get complicated of course.