According to Wikipedia, G. G. did the Pisa tower xpmt. Instead, as I thought, a "Gedanken". ***
"The gal is named after Galileo Galilei, a physicist who made the first measurements of the Earth's gravity, and who dropped items out of the Tower of Pisa to see if weight had a bearing on the time taken for them to fall."
bc thinks he may want to correctly correct the Wiki. and joyously awaits a free 60 micro-gal resolution sensor from the USGS.
*** My modern phys instructor (UCSB -- 1957) said G.G. posed the question, what happens when one cuts the rigid thread between two unequal masses while falling?
The talk discusses the non-SI, but not the experiment. And I would add the Eötvös confirmation.