I don't have all my feedback notes to hand, so here's a partial answer. (All errors due to memory loss induced by post-exam refreshments)
Principles of Flight 1hr, approx 44 questions
Aircraft General Knowledge 2hrs, approx 99 questions
Performance 1hr, approx 34 questions
Ops Procedures 1hr20, approx 50 questions
Radio Nav 1hr30, approx 59 questions
Law 1hr40, approx 75 questions
Mass & Balance 1hr
Instruments 1hr30
Flight Planning 3hrs
General Nav 2hrs
Meteorology 2hrs30
Human Performance 1hr
VFR Comms 30 mins
IFR Comms 30 mins
Time is not an issue on most of the 'general knowledge' exams, as you either know the answer or you don't - one of my group set a new World record by finishing VFR comms in 2 1/2 minutes.
Questions involving calculation or plotting slow you down, but the marks are weighted in favour of these questions, and the time allowed is usually adequate. The only exception seemed to be General Nav, which many people struggled to finish. Probably not what you wanted to hear, but by the time you have finished the groundschool brush-up you'll be doing these exams in your sleep, so you'll be well prepared.