In regards to cannabis and sleep your quick and dirty guide is:

CBD does not help you sleep by making you sleepy – HOWEVER if anxiety is the root cause of your insomnia CBD does have promising research showing its anxiety reliving properties and thus may help relieve anxiety and help sleep. You can vaporize CBD in which case the time of onset of effects will be rapid. Oral tinctures can work as well, just remember orally dosed CBD does not reach peak serum levels until 3 hours after intake – thus take your CBD a couple hours before bed. Milligram doses we have seen range between 20mg to 300 mg. Start low and see what helps you. Thankfully CBD has been shown to have very few side effects which are usually mild.

THC has research showing it can help people fall to sleep more quickly.

If smoking flowers using a bong, bowl or joint:

Some people recommend Indica strains – this is meaningless to the informed consumer. You want to see the lab test showing the cannabinoid and terpene profile and look for the higher concentrations of sedating terpenes like myrcene. High THC levels will also have stronger sedating effects. Any good budtender should be able to show you a test and explain the chemical composition to some degree.

If Vaping Oil

THC oil will work, or you can try a strain specific CO2 extract that is from a strain that has high concentrations of sedating terpenes.

If eating:

Research shows most people use between 5 and 20 mg of THC to aid in sleep. Remember if dosing orally time of onset can range from 30 minutes to 1.5 hours and last 4-8 hours.