Thanks for the try, but it's not the size of the marker I'm really struggling with. Its a kind of shift/scale in depth. Vuforia is getting the VuMark tracking done well on the HL, but they are like 1 meter behind the actual targets (should be right in the center. If I come close to my printed images they shift and scale closer to the point how they are supposed to be. Checked this with multiple Unity versions, all the same.

Okay, I'm getting good, stable, behavior with 2D image targets in the hololens, now.  It requires three things:

• The physical target image printed out at a specific size in meters. Assume 0.1 (10 cm) wide and .15 meters tall.  I like to display it on my monitor to make resizing easy and save paper. 
• When you upload it to a database, give the width of the image.  The database builder will calculate the height of the image for you. So, if your image is twice as wide as it is tall, and you enter ".1" (10cm) then it's height will be ".15"
• The ImageTarget object in Unity has to be scaled to "0.15" meters!  Maybe it really needs the larger dimension (height or width) or just height. Haven't figured that out yet. 

Works pretty well for me.  

I'm just learning this myself, and also having some trouble getting the hologram to locate correctly.

I do know that you have to scale the ImageTarget to be exactly the same size as the physical vumark.  

Also, the VR camera in the scene needs to be at 0.0.0.  I'm using Unity 2017.3.1f1

That's a well known problem with the size of physical markers, you can check it on other posts. I recommend you to check the size you set when creating the marks and the actual size that they have in real world, in paper, they must be the same.

Any Update here??