I use a northern brewer ss cfc and have no issues.
I chill down to about 165⁰ for whirlpool.
After that it takes about 7 or 8 minutes to go into the fermenter at 65⁰. (6 gallon batch)
I will time it eventually out of curiosity tho.
I too didn't want any copper in my system.
The stout ss cfc is...