I finished installing the second tonearm and inserting two new #304 stainless steel plates under the turntable. The plates are designed to match the dimensions of the optional air bladder base which I did not get with the turntable. They provide mass loading to the rack and a very stable platform for the turntable, separating the motor unit from the main chassis. The smaller plate weighs about 70 lbs and the larger about 150. Each plate is 2" thick and I refinished them for a smooth, satin finish. Note the reflection of the table's underside in the top surface of the plate in the first photo.