In reply I don't like the look of buckeye couplings on freight stock as most of British freight stock had three link, instanter or screw couplings. Some of the newer stock has a type of buckeye coupling.
But it's your stock and you can put any couplings on it.
This link should help you decide if you want to use Kadees ,this link should take you to the O gauge couplings, but you may want to have a look at the S gauge ones as well.
O Scale Couplers - Couplers - Shop by Category (kadee.com)
ATB
OzzyO.