Hello and welcome @Brian_P_1 
Unfortunately, I don’t believe quarterly is an available option at the moment. Though it has also been mentioned recently in this topic Stripe Payment Gateway feature request - #24 by Chaitanya_Khanna, so may be worth a dedicated feature request. 
I think the Subscription flow is to have people signup for the ‘freely available’ section of your site, and then subscribe to gain access to the gated areas. There may be other ways to achieve what you’re looking for though, but I’m afraid I don’t have experience of those. If nothing is popping out using the Search you may get more knowledgable replies from a fresh support topic. 