Let's make this easy for you: As far as the
UVb light goes, you absolutely must buy both a long (at least 18", 22" or 24" is better) UVB tube, preferably the much stronger T5 strength tube rather than the T8 tube that must be strapped to the underside of the mesh, within 6" of the basking spot, and replaced every 6 months, as opposed to the T5 UVB tube which only needs replaced once every 12 months, can sit on top of the mesh lid of the tank, and must be only within at least 11" of the Basking spot/platform. It must be at least a 10% UVB tube, or 10.0 (no lower, like a 5.0 or 2.0), and a matching length fluorescent tube fixture that is rated for a T5 UVB tube (rated for at least 24 watts). The 2 that are adequate for a Bearded Dragon are the 22" Reptisun 10.0 T5HO UVb tube, and the 24" Arcadia 12% T5 UVB tube, each of which can be ordered very cheaply on Amazon.com along with a matching T5-rated tube fixture as a "package deal"; The 22" Reptisun 10.0 T5HO UVB tube costs about $24 on Amazon.com (a fraction of the price if you can find it in a pet shop), and Amazon.com also sells a 24" T5-rated tube fixture with a Metal Reflector included inside it (yes, the 22" Reptisun 10.0 T5HO tube fits into a 24" tube fixture) for about $28. So for around $50 shipped on Amazon.com you'll have one of the best UVB tubes and a fixture for it for a Beardie that will only need replaced once every 12 months, and will ENSURE that your dragon will not end up with the very common Calcium Deficiency and MBD due to inadequate UVB and UVA light. This is not optional, it's a requirement that you must have BEFORE you bring home a baby Beardie.
As far as the time period/lighting etc., you're over thinking it, which is good I suppose, as it shows you care and are taking it seriously. But please don't worry at all about the Diurnal period of 3-11, that's a non-issue. Here's the bottom-line:
#1) Both your dragon's T5 UVB tube and his bright-white colored basking bulb need to be on every single day for at least 13-14 hours. Again, not optional. So in the morning if you turn both his lights on a 6 a.m., then you need to leave both on until at least 7 p.m., etc. It doesn't make any difference at all what actual times of the day you do this, nor do you need to black out windows and such if your work schedule is what you say it is. Just turn his lights both on when you get up in the morning, and be sure that they are both on in the morning for at least an hour or 2 before you feed him his first live insect feeding session, so he'll be warmed up and ready to eat and properly digest. Then in the late afternoon or early evening you give him his last daily live insect feeding, but you must be sure to leave both of his lights on for at least an hour or two AFTER his last live insect feeding session of the day, again so he'll properly digest and absorb the nutrition.
#2) NO CATS IN THE ROOM THE DRAGON IS IN. EVER. MUST HAVE A DOOR THAT LATCHES AND IS ALWAYS LATCHED. PERIOD.
#3) A baby can get away with only 2 live insect feeding sessions a day, but 3 is better. Each should last between 10-15 minutes, and he needs to be allowed to eat as many live insects as he wants in that 10-15 minute period. If using crickets or roaches you have to feed 1-2 at a time, let him eat them, then put in another 1-2, etc. until he either stops eating or the 10-15 minutes is up. Never leave any live crickets (or roaches in my own opinion) inside his tank at any time. If you don't have time in the morning before work to allow both his lights to be on for an hour and then be able to feed him for 10-15 minutes, 1-2 crickets or roaches at a time, then you'll have to feed him either size Large BSFL (yes, a baby can eat large BSFL because they are soft bodied and it will keep him from eating as many) or Silkworms, if you can find them. You can also feed him the large BSFL in the morning in a bowl (dusted 5 times a week in calcium and 3 times a week in a multivitamin powder), and then feed him crickets or roaches during his late afternoon/early evening live insect feeding when you're home and able to feed him 1-2 at a time and remove any extras that are left inside his tank.
That's pretty much it. Again, don't worry about the Diurnal period, the 3-11, etc. First of all, the breeder/vendor/pet store where he is hatched/raised/sold has not worried about it, and by keeping them in captivity anyway you don't need to worry about it, Bearded Dragons are not nocturnal, and really that's the only issue that presents a problem as far as feeding and light periods for people. Beardies will be fine on YOUR SCHEDULE as long as both is T5 UVB tube and his bright-white colored Basking Bulb are both on for at least 14 hours (longer is okay), his tank is both Pitch-Black and considerably cooler at nighttime than in the daytime (around 65 degrees is great, so no nighttime heatsource is usually needed at all), and he gets at least 2 live insect feeding sessions per day, 3 if you can do it. If you're home by 3 p.m. then do one feeding session in the morning before you leave (use the BSFL in a large bowl if you have to), then do the second at 3 when you get home, then do the third around 7 p.m. and be sure to leave both his lights on until at least 8 p.m., or if you like nighttime quality time/snuggles, feed him his third feeding session at 7 p.m. and let him inside his tank under his lights until 8, then take him out at 8 p.m. for snuggles....You'll be fine as long as you get him a very strong, T5 strength UVb tube and feed him appropriate live feeder insects that are dusted in calcium 5 times a week and multivitamin 3 times a week. The UVB/UVA tube is very, very important...