You have some great options there.
COB rush is so different from formal rush - so much more relaxed. I joined my sorority via COB after dropping out of formal rush. With COB (from both sides) I always found I was able to have real conversations without constantly getting interrupted by singing, skits, and rho chis.
I second the recommendation for comfortable shoes.
Best of luck, and be sure to keep us posted! (I love rush threads
)