A little help picking out my roster

So I am a bronze player and I'm trying to decide on a solid roster for my ranked games this upcoming season. I am an adc main and support secondary. My tertiary role is Jungle, and I would like to give myself a list of champs I want to be using this season, but it is quite long and I am comfortable with most of them. I need help figuring out how I want to shorten the list for each role and giving myself a ranking of my general skill with the champs. As far as my list for adc's I want it to be roughly 5-10 champs, with 3-5 of them being "Mains". My supports I would like to shorten the list to a solid 5 that I know I'm good with and 2 of them being my support "Mains". As far as junglers go I'm thinking a solid 3. Top and mid I already have 2 outlined for but need help solidifying my lists.

Now plz understand I'm not asking you guys to give me a list of champs I should be running. I know what the current flavors are but I want to make my own list and need help figuring out how to put it together. Any help on how to put my list together would be greatly appreciated.