Seeing as your opponent is top, they must be decent. I'd say normal, you can try defensive at first if you wish and see if you're dominating possession. I'm pretty sure counter attack isn't so good as they've got a DM, but you can experiment by putting it on and seeing if it improves things, but only if playing defensive.
As for arrows, I'd say none at first. You can put up arrows on your DMs if you're not winning to be more attacking. Then up arrows on your AMs if that's not enough. At this point you'd effectively be playing 3-4-3 due to the up arrows. Switch orders to attacking and whole pitch too.