The plant with little or no trichome production is most likely a Sativa; And, they do not always produce a lot of big trichomes.

If you have 50% cloudy...I would flush for 2 weeks and harvest. When you do this, your fan leaves will yellow and drop off as normal. When leaves yellow, this is a sign that the plabnt is using the stored nutrients in the leaves and is ready to harvest. This is why we cut the Nitrogen down in mid to late flower. This makes the product taste better.