Locating the mechanism position on the plate is best done by temporarily installing a Plywood plate 5/8" to 3/4" thick mounting board for trial and error mechanism placement. Some seats have thick heavy backs or heavy seats, so there is no formula on where to place.
The correct balance is when the user can sit up or tilt back with little or no effort while at a normal comfortable height. The seat is in sync with the mechanism when the user from a sitting position with feet flat on the floor clasps both hands behind their head (shifting body weight) causing the seat to gently tilt back. When satisfied, replace the plywood with a steel plate, or simply leave it in place. Either a Manual or Gas lift height adjustment mechanism may be used. We recommend using a heavy duty gas lift cylinder.
The trial board should be attached near to the rear due to the heavy seat back weight.