I was having the same problems with my left VUK. I changed my sleeve and the plunger but the problem came back. Then I fixed the alignment of the whole assembly. This worked for a while but the problem came back. Finally, I fixed the alignment of the coil against the assembly using rings between the coil and the bottom bracket. This tightens the coil and pushes the screws lower in their oval hole so they can't move anymore.

This is documented here. The link also points to other links for more suggestions if that's not your problem.
https://www.maaca.org/viewtopic.php?f=22&t=23493
The trick to use a slurpee straw for the alignment really helped.

The coil is strong enough. I did not have to change it.

Here is a picture of the right ramp
http://www.silverball-magic.com/smagic/my-machines/sg_rightramp.jpg
It's hard to know which angle you need from your description.
For me, the "guide piece that feeds the ramp" is the top of the right VUK scoop
http://www.pbresource.com/stargate/gtb-31174.jpg
which is obviously way above the ramp.