I considered seam sealing the Stephenson bag, but if you close it off and lean on it, it does nto lose much air through the seam. So, IMHO, seal sealing is not going to get you very much, especially when you consider the entire "filling" process.
I got a Pillow Pump. It's fast. It's effective. I like it.
Edit: If you haven't looked back at Page One of this thread, do so. An abundance of pictures and comments.