For 35 years I worked a 2/2/1...two swings, two days, mid. My last few years we were allowed to modify it somewhat, so I always worked 4-12, 3-11, 1-9, 7-3 and 11-7, all 8 hour shifts. For my last 15 years or so, I was always the senior guy on a 2 person mid and never allowed sleeping. The Center had 6 areas of specialization, most of the other areas (and my area, when I wasn't on) the guys traded 3 on/3 off and slept. It's been going on for over 20 years & FAA will never be able to stop it. Now I did occasionally go bobble-headed, but NEVER slept. Wasn't paid to.
Second job? None of FAA's business how one spends his off time. For 25 years I owned an aviation market research business, it had no effect on my FAA work, except to make me more knowledgeable about aircraft.
The young kids today do seem to burn both ends of the candle, but that is a personal choice guided by their entitlement mentality and buttressed by the union. The pay is great, but damn, the quality of the people has just plummeted. I would never urge a kid I thought highly of to take this job in today's FAA.