In general, indica strains tend to be more sedating and effective for inducing sleep. Keep in mind that vaporized cannabis is effective for 1-2 hours. This may be adequate if you only have difficulty falling asleep at the beginning of the evening. On the other hand, if you find that you are waking up in the middle of the night and having difficulty returning to sleep, I would suggest you consider an edible form of indica approximately 1-2 hours before bedtime. If you are not aware of an effective edible dose, I recommend starting with the lowest available dose, typically around 5mg.
Growers and manufacturers of concentrates and tinctures as well as edibles are beginning to make products that have a relatively high CBD to THC ratio. These products may offer many of the benefits of cannabis while decreasing the psychoactive effects associated with THC.