It's an overkill to spend lot of time on choosing specific websites. 99.9% of the times performance will be the same across all sites. The conversions across different sites would be attributed as follows: 0 0 1 0 0 0 2 0 0 0 0 1. With lot's of 0s... And even if a website brings e.g. 4 conversions one month, most probably next month you will have 0 conversions once again.
If you would like to learn more about how to setup a remarketing campaign on Google Ads (and much more), you can have a look at my book on Amazon, thanks!