Thanks for everyone's input. I should have made it clear that I agree that this is only a push stick and the cut does not need to be dead square, but I was also thinking about similar cuts found in other furniture pieces, which is why I wanted to ask about the best technique for obtaining good accuracy. Your advice would help me with those future cuts.
Anyhow, I appreciate everyone's input on this matter. I'll stick to the basic hand tools for now.
Cheers.