Determining Yield?

I'm interested in finding out around how much I will yeald when these plants are harvested (rough estimate). Let's say that out of twenty five seedlings, ten good plants are left (being way conservative). these are outdoor strains (mixed seed pack) so I was curious to know how much I might get!

What is a good yield per plant anyway?

It is impossible to say. There are just too many variables when growing outdoors (and indoors for that matter) to take a guess about yield.