You know, I struggled with the same decision when I started Rilutek last March. I had a pretty regular daily schedule of getting up around 6:30 am and going to bed at around 10:30 or 11:00 pm and I had trouble working the every "12 hours on an empty stomach" requirements of the pills into my day. Because I am one of those people who absolutely has to eat as soon as I wake up I figured out that the best times for me were 10:30 am and 10:30 pm. That time was far enough after breakfast and supper as well as being long enough before lunch to work well. That worked for a while until I started to have more trouble swallowing and found that I was always hungry and always eating. The result was that I never had an empty stomach for the pills. When I asked my doctor about it and how important it was to take the pills at the same time each day on an empty stomach he said that it was more important to not lose weight than it was to keep to a rigid schedule.
I don't know if you have trouble swallowing pills but I found that my taste buds really suffered from the Rilutek when I tried to swallow them with water. I would put the pill on my tongue and then wash it down. Bad news, you don't want to have that thing in your mouth for any longer than it takes to get it down. I now take mine with yogurt or apple sauce, anything to help it go down fast and keep it off my tongue.
I'm sure that like most drugs this one does work better when the instructions are followed but at least for me it was either modify them or stop taking it. Good luck and I hope my story has helped.