Awaiting an official solution, I exposed my own here: Reflow - Testing order and digital delivery considerations - #6 by elroot.
I’m among those who are waiting too… In the meantime, as I have already done about blog (a subject not covered by BSS & Co), I’m developing my own internal full solution (digital dedicated) which is independent of any API except the final payment gateway one (i.e. Stripe). This doesn’t say I will not use Reflow, but it means I think it’s always better to have two solutions and avoid to stay dependent from outside.