NET pay is not the best to use for comparison. Which health plan did you choose, how much did you contribute to your 401K, how many exemptions did you claim?
My first year GROSS W-2 wages at Atlas were $47,875 as a 747 FO. That was 2013 but the pay scale hasn't changed. I NEVER voluntarily worked on day off (VX), I was in the hostile fire pool and I did drop 3-4 days per month MIL. I got involuntarily extended into a day off maybe once.
I was paid a range of 50-73 hours/mo with an average of 61 hours of pay after completion of OE.