"Possible temperature effects were evaluated by using radiant parabolic heaters to artificially heat the apparatus and the air through which the light-beam passed. These experiments showed the interferometer clearly was sensitive to artificial heating, and so steps were taken to eliminate the effect. Strong radiant heat sources, it was learned, would badly skew the apparatus if focused upon only one arm or pair of arms of the iron cross-beams. Equal heating of the apparatus had no such effect, but the metal arms were nevertheless covered with a one-inch cork insulation to guard against radiant thermal effects. The light-path was given a glass housing, which stabilized the temperature inside, and later, a light corrugated paper cover was added over the glass cover, which did not affect the ether-drift, but further protected against possible temperature variations. Low-level thermal effects were also evaluated, as from human body heat, by having the recording assistant stand in different locations while the apparatus was turned and operated."
Which negates Shanklands criticisms completely.
I think if I were a physics student today, I would look to upgrade Millers experiements to even greater sensitivity which is certainly possible using more modern equipment - not that Millers experiments were not accurate and sophisticated, but nowadays we have lasers

. This does not seem an overly difficult or expensive experiment to repeat and in that sense it offers a very high ratio of bang-for-buck given that its implications would force a re-write of accepted theory. Of course, no-one would believe you, but if you could get a positive result and overcome the skepticism, the Nobel prize ought to be yours.
Could this not be tested with the Ligo interferometers? (They might as well do something useful with them).
Also Ligo in space, Lisa, is putting interferometers in satellites. Can they be used to repeat the experiment and measure the drift away from Earths influence?