I light my tank with LED's. My primary reason for a split photo period is purely selfish... I have the lights come on in the morning shortly after I get up so I can enjoy the tank while getting ready (and be able to look for any issues that occurred over night). I think my morning light period right now is 4hrs (6am to 10am or something). I have the light come on again shortly after the normal time I get home from work and it stays on until 10pm, so about 4.5hrs PM cycle.
I am no expert, maybe someone will think I'm doing it wrong but until I see adverse affects I'm going to keep doing it this way. After all the whole point is to be able to SEE and enjoy the tank right?