Side sleeping baby and wedge

K ✨
Hi girls, I'm just wondering if anyone else has a baby that will only sleep on their side. My 10 week old will not sleep on his back for more than 10 minutes but on his side he sleeps for hours. We only just figured this out a couple of days ago so have been putting him to sleep in a high chair with the back reclined. I supervise him the whole time so I can check he is breathing as I am terrified of SIDS. 
Anyway seeing as the side sleeping is working so well I'm wondering if anyone has used a wedge for their baby in the cot of bassinet ? Are they safe? And do you have any recommendations of which one to buy? Xx thank you