Time to command best guessed at 3-5 years (don't be lead by the agencies telling you less time - hasn't happened!)
Contract is for 10 days off a month, plan on that, anything extra is a bonus. The "good old days" of working 14 days a month are long gone. Bear in mind if you ask for days off near the start of one month and near the end of the next, you will be on the road for 30+ days in between. Travel to base on your days off to start work too, so our long haul commuters are getting 7-8 nights home a month.