If you have B412 and S76 why you don't think about Bristow? You would likely be sent to Nigeria with CHC, but Bristow have many more bases and helicos in Nigeria than CHC. They have S76 and B412 in Lagos, Port Harcourt, Eket and Calabar, Warri and Escravos and have just introduced 6/6 roster to compete with CHC. Sadly they have not said what they will pay yet or if additional benefits will be part of their new deal. CHC has only Port Harcourt with just the 7 S76 and are changing everything to Canadian way of doing things, so many feel standards is slipping. Also, with Bristow money (US$) is paid equal amount into your account every month, but with CHC money (Canadian$) has to be claimed for every month, else you will get only the basic pay and the pay varies every month depending whether you are on tour or off tour.
With CHC in Nigeria all SFOs are nationals and fly a lot in the right seat. With Bristow they have quite a few expat SFO. With your hours, but low offshore, Bristow would offer you SFO, followed by promotion as soon as you have enough offshore time and as you fly 80+ hours every month you'd soon get that. Also, with the new roster you can ask to work 8/4 roster if you want more money or flight time, something CHC refuse to offer.