The backflow limit on the teleporter dialog isn't wired up yet. The idea is that it will be a limit on the number of queued up bots in the out directory for outbound teleporters at which point the teleporter will stop teleporting.
Right now, outbound teleporters teleport out everything they encounter when they encounter it. Changing the size or motion of the teleporter will give you some control over this I.e. smaller teleporters will on average teleport fewer bots per unit time.
Inbound teleporters will teleport in up to the specified number of bots (if they exist in the inbound directory) every specified number of cycles.
Teleporters arn't really designed to queue bots like you want to do, but tweaking these parameters should allow you some course grain control over this. Note that there is no ordering gurarentee on bots queued after teleportation. Right now, it's a function of the file system DIR order of the random names I give the dbo files on disk, so probably not FIFO or LIFO but more like random.
