I haven't heard of sunseed bedding before. In general, though, I tend to stay away from particulate bedding - whether it's Yesterday's News, Carefresh, or what have you. Instead, like many other hedgie owners, I use fleece.
Hedgies don't accidentally eat fleece (particulate bedding can be eaten & cause an impaction), they won't breathe it in (think of how dusty Carefresh or shavings can be... and the effect on a hedgie's lungs), it won't hide blood or other signs that hedgie is unwell (messy poops, vomit, blood in urine...), it won't accidentally stick to you or hedgie and travel over your home/show up in your laundry/get stuck to your clothes, it won't get stuck to a male hedgie's penis and cause issues there...
If that's not enough to steer you toward fleece, how about the fact that you've noticed Milo likes his blanket? Imagine the whole cage floor as a blanket!! And he can still have smaller fleece blankies to snuggle up with.