I have always been intrigued by the HS-80. I believe the recommended way to set it up is so that it is directly opposite the motor. In this way the forces on the platter due the belt should cancel each other out and there should be minimum force, and thus noise, on the platter bearing.
The disadvantage, as I see it, is that you have greatly reduced the contact area of the belt with the platter. With a thread the contact area with the platter is already very small and with the HS-80 it is further reduced.
The "HS-80 MS" illustration avoids this but does not minimize the forces on the platter bearing.
It is an interesting choice of trade-offs. Set up would be critical. There are variety of formulas for pulleys, belts, contact area, wrap angle, coefficients of friction, and so forth but they were a bit overwhelming to me.
The disadvantage, as I see it, is that you have greatly reduced the contact area of the belt with the platter. With a thread the contact area with the platter is already very small and with the HS-80 it is further reduced.
The "HS-80 MS" illustration avoids this but does not minimize the forces on the platter bearing.
It is an interesting choice of trade-offs. Set up would be critical. There are variety of formulas for pulleys, belts, contact area, wrap angle, coefficients of friction, and so forth but they were a bit overwhelming to me.