We did end up buying the Tucker Sling / Wedge combo for our little guy.
He sleeps on his tummy and was always sliding down from the wedge t under his mattress. So, I caved and bought the Tucker Slinge / Wedge combo. I tried so hard to get it approved from my insurance co, but had no luck b/c it was of network unless I could find a DME (durable medical supply co that was in network – could not). I bought the wedge with the sling for 6-16lb. My guy is about 15 lbs now and can still fit it okay.
The first night we got the sling, my guy (at 11 weeks) slept 8 hours through the night and did not wake up. He usually would wake himself up by puking. He slept so comfy. Knowing the he slepts on his tummy, and the risks associated, i just felt better having him strapped in and safe.
Thumbs up and approve!
Good luck.