The bibliography on Galileo's experiments is really extensive.
For what it's worth, Alexander Hahn's most recent in/ex-cursion in the history of mathematics have resulted in
"The Pendulum Swings Again: A Mathematical Reassessment of Galileo's Experiments With Inclined Planes, to appear in the _Archive for History of Exact Sciences_. See:
According to Hahn, in the early 1950's Alexander Koyre asserted, contrary to commonly held thought at the time, that Galileo's actual experiments were sadly inadequate and that he relied primarily on armchair or thought experiments. This view was challenged in the early sixties when Thomas Settle demonstrated that Galileo could indeed have carried out with satisfactory precision the experiments with inclined planes that he describes in the Discorsi. Confirmation of Settle's argument came in 1973 when Stillman Drake perused Galileo's unpublished working papers in the Florence Biblioteca - this collection is known as Manuscript 72 or Codex 72 - and found written records of Galileo's experiments.
I'm not quite familiar with this issue, so the sooner I shut up the better.