Late reply and IANAL but I don't believe you can actually do a token model where the people buying tokens early on pay less for them than they will be priced at later. Pretty sure that doesn't pass the Howey Test[1] because there is an expectation of profit. And if there isn't an expectation of profit there is little to no incentive to have a token, kickstarter would work.

1. https://consumer.findlaw.com/securities-law/what-is-the-howe...