Unfortunately, there is a 99.9% chance of your SARMS being fake, since they can be sold legally only as reseach chemicals, and no reputable source will sell capsulated forms of SARMS. Usually, they will lace them with prohormones in order to lead the user to a deception, because they will get performance enhancement. However, this is a dangerous situation, as prohormones have side effects that do not take place with SARMS, and consequently one does not have the chance of preventing those by using the proper ancillaries. Therefore, in the best of the cases, you would be getting bunk SARMS.
If you want to get real SARMS, make sure that you have a reliable source. Personally, over the years I have used the SARMS of many brands, and so far only sarms1 were able to always deliver real and high quality SARMS for me. Therefore, I can personally vouch for them. Besides, their customer service is really good, and they will always go an extra mile for their customers.
I would say that 8 weeks is the minimal cycle duration you want to do for sustainable resylts, being 12 weeks the recommended cycle duration.
As for the vials, 1 vial of cardarine will last you for one month (4 weeks), and 1 vial of ostarine will last you for 2 months (8 weeks).