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Role play player limit?

If the GM can handle it, then it is possible. It helps that you're keeping them in groups of eight, but if everyone comes together then things could get quite messy. The more people you have, the harder it will be to keep things organized. But on the bright side, you also have more minds together. It really depends on what you (as a GM) can handle. Some can handle several scenes with several characters while others prefer smaller groups. Larger groups have their pros and cons and the same goes for groups with only four or five members.

If things get too confusing, you could always look for a Co-GM or two. It's definitely doable, it'd just require more work and planning.