My thoughts on this,,,
scenario, you have a first x collie grey which you have put the time into training for obediance trials and theres a good chance you would win all day long
take the same pup and from day one just give it the basic training and let it find its own feet and theres a good chance it will perform well in the field
try and combine the two and it gets shady, I reckon all the obediance training for trials would hinder a first x in the field
scenario two,,, If I was and I,m not but I were to try and win some trials I think a 3/4 bred would be the way to go, a