I'm not as young and invincible as I used to be. I hardly, if ever wear my live jacket. I know I should, but ya know how it goes...

Nothing wrong with the life-jackets in my boat. I'm sure they will work great, if I was wearing one. The problem with my lifejackets is comfort. They aren't comfortable to wear. My main concern is getting knocked unconscious while getting tossed from the boat. I don't have a problem swimming. I boat swim in the lake all summer, and have a pool when not on the lake.

My main concern with self-inflators is wearing one during early spring and late fall over/under my winter coat.

Can i wear a self-inflator under my winter coat?
What type of self inflator will open if I'm unconscious and unable to pull the cord?
What are the downsides to self-inflators?