ask for VR goggle lens

hi, i just made a VR cardboard last week based on google cardboard.
currently im using 5x loupe magnifier from ebay (dia 50mm, fl 40mm).
the problem is i can still see the divider/separating wall between image. so it's feel like looking through box tunnel

if i move the lens close to the screen, the image will be blurry because the focal length
so my solution is ordering new aspherical lens from surplusshed that have dia 40mm fl 30mm so i wont see that divider
i can't find any other aspherical lens that have 40-50mm dia and fl 15-25mm, maybe if someone here know where to buy, please give me the link.

i order 3 kind of fresnel lens because i want to try dual iphone 4 like infiniteye, but i think it's gonna be a problem because infiniteyeages on left and right isnt exactly the same

and the main point is i want to ask everyone, "what kind of lens that you ever tried before ? and which one is the best (no divider, large FOV, good focus)"