I'm not sure about King's Kush, but Train Wreck is a longer flowering plant. To get maximum yield and potency from it you will need to flower for about 10 weeks. Also you will want to look and see if you can find the average flowering time for the King's Kush strain and follow that as well. Other than strain type and flowering time to get a healthy yielding plant, the key is the right environment and nutrients for your babies through the entire course of their lives. Also making sure the light is as close as possible without burning your plants. This will ensure good node structure. The more nodes, the more buds you will have. If you are curious on which nutrients to use, I'm sure you can ask and a lot of people will have an entire list of suggestions. I myself go with a select few such as CNS17 - Grow and Bloom. (this has pretty much every main nutrient your plant will thrive off of) Also Budswel, used during bloom and Dark Energy which can also be used in a foilage spray. Other than that as long as you PH your water and take good care of your babies, there is no reason I don't see why you wouldn't be able to produce a 400g+ yield after only a 2 week veg period.
Hope this was some help. Good luck to you, an let me know how it pans out.
-Ellisdee25