Two things - my understanding is that hens need 14 hours of daylight to lay well. If you are going to light them, have the light come on early and let them have a natural dusk, so that they go to bed sfaley.
The other thing is that I read recently that a hen has about 600 eggs in her - they're all there when she's born. They will simply ripen over time. So if you force the laying, she's run out of eggs quicker.
I've bought solar lighting but haven't installed it because I like to give them a rest BUT if you have customers waiting, then it's a judgement call.