Reverb Chamber out of an old farm silo

We live on a property in regional NSW and we are about to commence our studio build (21m x 10m building). Last year I did a bunch of recording inside an old silo on a nearby farm. The reverb sounded fantastic. Now, the farmers have offered to give me a silo. So, the plan is to move it from there farm to our place. Then, place it next to the studio, install a speaker and microphone in it which is at all times connected to the control room so that with the touch of a button I can send sound out to the silo reverb chamber. The silo they are giving me is different from the one I recorded in earlier, but yesterday I climbed inside it and had a sing. It is a much bigger reverb, but still, I loved it. Would like to know people thoughts on my plans. The silo is corrogated iron. It is (very roughly, at a guess) 5m wide by about 9m heigh i will check these measurements in the next few days. Should I install a speaker on the bottom of the silo and a microphone at the top? Should I install the microphone (or speaker) on a motorised pulley system so I can bring them closer together or futher apart to change reverb times? All from the comfort of the studio chair of course? Any thought would be appreciated. Vic

Vic - the idea is to have as little of the direct speaker sound in the mike signal - that may mean building a baffle in the centre with the speaker (preferably two for stereo) on one side and the mike (s) on the other as all you want is the reverberation, not the original signal.