If you don't have any previous experience with SEO i'd rather go even lower than 30k/80, if possible a niche that has about 10k competing pages and daily traffic about 60-80 as it will be way easier to rank high for it. Also do extensive analysis on backlinks of top 10 ranked pages, to see where they get their links (and steal some of them) and see how many of them are using anchor text for their backlinks. For category keywords, you can go even lower if you find any microniche like that, preferably also below 10k SEOC.
You can also do the stuff above 30k, i just suggest you pick an easy project for your first niche. Make it your "learning project" and get experience from it, learn new techniques, and then go for the harder niches, that might take more time to penetrate.
Hope this covered all of it
