I don't actually have a coherent strategy for Off Shore, rather a few simple tips. Here is the map:
I'll call the vantage point up the long ramp a crow's nest for convenience.
For all regular waves you can sit up in the crow's nest and do extremely well money-wise. I've played waves 1-4 a number of times and can easily get $20,000 simply sitting up there and going for the rampage and kill streak bonuses.
Wave 4 brings a juggernaut but it's very easy to simply flash and kill him before he reaches the top of the ramp.
Wave 5 is the first wave with a helicopter and you should run around for all jugg + helo waves from there on. The map has tons of cover and stairs and hall ways to run through for those waves.
Off Shore has a brand new wave progression. Let's call it a Tier 6 map.
Jugg + helo waves: 4-5, 9-10, 14-15, 19-20, 24-25, 29-30, 34-35.....