Life jacket for big infant?

I have a 6 month old. She's in the top 98 percentile in growth chart so she's a tank. We have a Sterns under 30lbs Type 2 but her head can't move in it and she can't use her arms. Arms are forced out to her sides away from her body. She's miserable in it so it makes the time on the water pretty much a beating. Any suggestions of other types we can try? We've been looking online and only have a Walmart close to use. Will make drive to cabelas or bass pro if something better. Not clear if she still has to have the part that keeps head afloat in the back or not? Seems after 30lbs you don't.

If she weighs 30-50 then she qualifies as a Child and there is a little more leeway on choices. Still, many PFDs will have a built in head flap. Take a look a stohlquist.com. They carve their children's PFDs to allow more body movement. Still very important for her to have a children's PFD that has the crotch strap to prevent slip-through.

http://stohlquist.com/kids/kid-s-lifejackets/nemo-infant-child.html

No she is still under 30. I checked out this link but only lets you get childs size for over 30

I don't remember where we got it, but my son hated every life jacket we tried except this brand. Best thing is, they are made in TX. Not sure if they make an infant one. But might call them.

http://texasrec.com

And they don't hold water and drip for an hour after kids get back in the boat.