Popping a full pack of ten sativa seeds and keeping only the best plant is standard practice for anyone serious about a line. Sativa crosses tend to throw a wider spread of phenotypes than stabilised indica hybrids, with noticeable differences in stretch, leaf shape, and terpene profile between siblings. There is a step by step hunt log for one of the Haze lines on https://hazesativaseeds.com that shows how the grower narrowed six plants down to one keeper. Cloning the winner before flowering is the part most people forget.