Intro product vs. Signature product timing

In online business I know I need a great free opt-in offer/product first to build my list, then some way to give people value/results ahead of time for free (podcast, blog, etc.). I’m currently doing one-on-one coaching. My question is once I am ready to create and sell a group-coaching product or an e-course, is it better to focus my efforts on creating the big signature product I envision (and beta test it before launching), or is it better to create a smaller, cheaper introductory product first and get it selling before creating my big signature program? Does it matter much which comes first?