In standard load balancing (often called "Round Robin" or "Weighted Round Robin"), traffic is usually split linearly. If Server A has a weight of 10 and Server B has a weight of 20, Server B gets twice as much traffic.
Look at your traffic logs. Is your growth linear (1, 2, 3...) or exponential (10, 100, 1000...)? If it's the latter, linear load sharing will eventually crash your smaller nodes. log10 loadshare
Assign weights based on the log10 of the server's capacity. A server with 10Gbps capacity doesn't necessarily handle 10x more "complexity" than a 1Gbps server; using a log scale helps find the "sweet spot" for performance. In standard load balancing (often called "Round Robin"