What size are your Jets? It sounds like you may have a size large. If so, you may want to try an XL. I have a size 9 shoe, use XL jets for both drysuit and wetsuit diving. For DS I use an XL springstrap and for wetsuit I use a L springstrap. I have broken both of my feet (5th metatarsals) and need a fin that is wide for that and I also had to have surgery on the dorsal aspect of my right foot, so the fin pocket needs to be quite high in order to avoid irritating that site. I have found the XL jets worked great with the right size spring strap.
I have to agree with the other guys, you can't stretch these boots. At least I have never heard of anyone being able to do so.
Also, how much bigger is the Turtle boot pocket than the Jet boot pocket? After looking at the Turtles, I thought that they were about 3/4" wider and 1/2" taller than the Jet's pockets?