Voodoo2, what you are looking for is CHC Global Ops. The head office is in Vancouver. They are always looking for fresh fodder to send to Africa.
You will need an ATPL(H), IFR and night. You have the S61 so that's your ticket into CHC GO. You can forget Thailand or Malasia for awhile. You'll have to take your lumps first then you can get somewhere nice.
In reguards to your question about the transfers policy, there isn't one. Every tour is an adventure. You will be sent to a base for an indeterminate period and then before you even get comfy you are off to another one with minimal notice or you could stay at a base until hell freezes over or until you screw something up and they remember that you are there.