Wait step prior to a stream

Hi there,

I'm setting up a stream cadence which casts every 4 weeks. We have a smart campaign set up to add leads to the stream; however, we've discussed wanting to wait about a month (or 28 days) or so before any lead gets their first email in this stream. My initial thought was to add a wait step prior to the add step; but if so, we could run into the issue where a lead would skip a cast and end up not getting their first email for nearly 8 weeks - i.e. Next casts are 8/1 and 8/29. Lead meets criteria on 8/2, waits 28 days, so they miss the 8/29 cast and end up on the next one 4 weeks later. I've played around with a few different wait step options, but nothing really achieves the situation we're hoping for. Has anyone else solved for a similar situation? Let me know if I'm going about this the totally wrong way. Thank you!