@lancerobrts, From what I know of Sparkle I don’t belief you can auto-redirect a page to another page based on time. The possible other way you can do it is by using the “Advance Form Submission” where you can nominate the URL after a successful send.
As a designer I don’t see it a problem being sent to a thank you page. That way you can flesh out the page to accomodate for a “warm lead”. Also the “warm lead” can continue to where they’d like to go with your main navigation still being present.