Unless you consciously breed in the CBD allele, you won't have much in the way of CBD content. It just won't be high enough to have much of an actual effect. The reason is that one of the criteria most breeders aim for is potency and breeding for this trait results in you unconsciously breeding out the CBD allele. The CBD and the THC allele are both codominant and so the presence of both produce an intermediary amount of both cannabinoids, reducing potency over a homozygous THC allele strain.
I disagree with your statement that the CBD content in indicas is what is mainly responsible for the couchlock in indica strains. On the contrary, it is actually due more to things such as terpene content. The idea that indicas are very high in CBD and that this is what causes couchlock is just another pervasive stoner myth. It's repeated so often that people don't really bother to read up on the subject to see whether it's really true or not.
That is not to say there are not CBD does not have some very interesting properties. In fact many people suffering from anxiety and other conditions find it very helpful.
I might add that you'll find a lot of landrace cannabis strains that we would call 'sativas' are often naturally high in CBD. Especially if they're charas varieties.
