Preferably twins - same size and weight but if there is a little difference you will be ok.
I am using small lightweight toyshop hoops mostly throughout the course. The diameter of these are the length of my arms. They are naked with no tapes of any kind.
You can use any small or large hoops though and can use naked or taped hoops.
My recommendation:
Use and try all that you have. Try all your hoops available and use what feels best. BUT:
It is easier to learn the moves and transitions with a smaller hoop because you can manipulate them and manoeuvre them easier. They fit in a smaller space so you will be able to play in tiny spaces. They also don’t damage furniture, etc.
Once you can do the moves confidently with your little hoops, then it is a great idea to try with bigger ones. Bigger hoops will get you fitter and increase the workout and make your shoulders stronger, too. Bigger hoops you will be able to spin on your body, too so eventually you will be able to perform all your on-body and off-body moves without having to change hoops. These are just recommendations, obviously you use what you like.