"Least Load first" balancing

[Dachantenne]

I'm about to set up a pfsense connected to three WANs. I found tons of information on how to setup the load balancing to use all three interfaces and it always says the traffic is "equally distributed".
But does that mean:

1. Lets say we have 16 active connections. Would they be distributed (e.g.)
   WAN1: 5 connections
   WAN2: 6 connections
   WAN3: 5 connections

OR

2. We have a total of 100MBit/s currently used
   WAN1: 33MBit/s
   WAN2: 34MBit/s
   WAN3: 33Mbit/s

On another firewall (we'd like to replace with pfsense) there's an option to select the interface with "Least Load first", meaning connections are not distributed just by amount of connections (like Round Robin), but by bandwith usage - which is exactly, what we need.
Connections can either be video streaming or web browsing, so it would be bad to just distribute by amount of connections and ignore the used bandwith of each interface as 5 connections of video streaming may use more bandwith that 10 connections of web browsing.
I don't necessary need one connection to be split over multiple interfaces, but just a more or less equal distribution for new connections, where the interface with the least load is preferred.

[jimp]

Multi-WAN load balancing has no concept of load testing, so that isn't possible. It's purely connection-based round-robin style. The most you could do is set gateway weights to send a larger portion of connections to a specific gateway but that's a static setup, not dynamic based on load.

[Dachantenne]

Damn, that would be such a nice feature...

Thanks for your reply @jimp :)