There isn’t a rule that I know of but you’d be better to sign up using the Rita Ora promotion as they have an additional free draw.
Once you’re signed up would you mind sharing your user number here? How many users now? It’s the most active thread and helps some of the crowdfunders tack user sign ups.
I hope you find this forum a useful place and keep coming back to learn and share what you know. Something tit bits you hear or stuff you see online is helpful to other investors or beginners looking to learn.