IMO I'd say get the best quality you can! THAT is the best way to improve existing 'birds' (flock to me).
Believe me I know. Starting with non quality birds and mating non quality takes a long time to find ANYTHING suitable. The imperfect trait of hens and the imperfect of cockerels put together are more likely to produce duo imperfections that linger for years in the flock. To get GOOD improvement begin with the best you can get your hands on and do selective breeding.
Hope that offends no one but it is what I have found to be fact. I am still weeding out narrow backs, high held tails and cockerels that aren't high on their legs.
I got two really good Cockerels from Fred that I will be breeding to my best few girls this year. The rest are for egg/meat only. Meat and some eggs for my consumption and the rest of the eggs to help buy Non GMO Amish ground layer mash feed.