AI'm only familiar with Wilton's tips, as those are the only ones I can walk into a store near me and purchase. I would say tip 8 or 9, but you may have to order those online.
If you have a coupler you can use that to make the bigger round circles.Just don't put a piping tip on it. They are round.
Also, if you know how to make the parchment paper cones, you could just cut the size that you need. That could also work for a throw away piping bag without a coupler or piping tip. Just cut with scissors and pipe on wax paper till you get the size of round ball that you need. Good luck and let us know how it comes out. This is just my idea of what I would try to get those circle borders piped if I did not have the bigger round piping tip.