I have the Zeintop and have had the same issue. One side locks down fine while the other side will just not quite catch. The problem I have is that the handle on the latch on the top hits the body of the car about 2 or 3 mm too soon. In my opinion, it's just the nature of Zeintech's fabrication. If the handle had a 10 or 15 degree offset or kink, then it would work fine. Part of my issue is that the top is not perfectly symmetric, creating a bigger gap on one side than the other.
I solved my problem in two ways, repositioning the spinlock in the car body for maximum "inward" placement. There is a little play and I just tightened it in that position. Second, I played with the shims on the latch mounts and through trial and error finally found the best configuration. Not perfect, but close.
Finally, when I put the top on, I use a 10mm box end wrench to hold the latch tight. I put the box over the latch and wedge the wench under the body sheet metal, padding it with a rag to keep it from rubbing metal on metal! Not perfect, but it stays locked!
