That first gear from the 7750 chrono module is definitely a problem sometimes. If you press it down firm for a tight fit to pinion, and to get least friction against upper bridge, then there is height mismatch with the next gear. It is really a matter of give and take with those two gears, but if you do not have a smooth output already with the first two gears, you can forget about the output on the later gears.
What I find strange is the height mismatch on the last two gears. There is a tremendous problem seating the final gear when installing the bridge at this point. To solve this I have been inverting the usual position of the second to last gear, to ensure more meshing between the last two gears, so that the second to last gear is installed upside down with the nickel-plated pinion facing up (exactly opposite to what Chris shows in his video).
There is also often a problem with the way the jewels are set in the final bridge: in fact that is why the movement factory is installing that little gold-plated washer on the final gear, to alleviate this problem.
Finally, these gears need to be absolutely clean: I am constantly manually cleaning them and examining them before final installation. Any little dust or fiber will impair functioning significantly.