I would go with the default airflow which on these stock type cards is out the exhaust or shown as with the green arrow. But actually I would test both and see what happens over 6 hours average, the reason being the setup in your room has an influence.
It could be more important where you place the rig relevant to the nearest window or cold air source I think. I guess would exhaust towards the window but I saw one video where he setup like a circular cyclone effect from air coming in one window around the room and then back out the other window. I've no idea if it actually worked as fluid dynamics and chaos theory comes into play when considering complex free airflow so who knows but it sounds a good idea in theory.
I've tried to pipe cold air towards my own rig but Im fairly sure the pipe way too small. Originally for cold water, also I have a great big tube that would swallow my entire arm to go from a window to the rig but it would be slightly awkward to snake through the entire room. I need a bigger clear room is the main point there, re OP we cant easily tell you without seeing the wider context and you are just better off testing all scenarios yourself if at all possible