3 shade lights that are minimum of 48” long are best for 8’ tables. Center of table from walls is 82"x 104"
See PDF below of Measure for Light Location
Try to avoid halogen light bulbs as they run very hot and damage your table.
4 shade lighting or lights that are 60” long are best for 9’ tables. Center Of Table from walls is 85"x110"
Lights that are hung at 60” from floor or 30” above tables provide ideal lighting situations. Shown below is a chart to show table and light positioning.