I find that extreme lack of sleep pretty much destroys my cognition and memory. Without pot or sleeping pills, I'm lucky to get 2 hours of sleep in a row. Additionally, when I wake up, I need to take my carbi/Levo thus pushing my daily intake up. I try my best to keep my use of Carbi/Levo down as much as I possibly can.
I've had scrips for all kinds of sleeping pills and I hate them all. They all have me groggy and running into the walls the next day. Pot doesn't do that. I sleep and wake up nice and clear headed.
Not being a smoker, I prefer to not smoke. But, as I said before, I'm a bit wary of edibles because the strength is so unreliable. I have had a good experience with what they refer to as concentrates. They are generally tinctures often mixed with something that improves the taste, like honey. The ones I get are in dropper bottles so you can go one drop at a time until you find your best dose. You also can use these without calling a lot of attention to what you are doing.
I personally do not like the feeling of being "high" so I don't care for sativa. My use of pot is strictly to relax, relieve muscle cramps, relieve pain and sleep. To that end, indica works for that.
Here is a website that suggests specific strains for your desired effect
http://www.medicalmarijuanastrains.com/strain-guide/