ZBrushCentral

[IMM] insert mesh stretching

i created a new IMM brush which i want to use to alternate between the different IMM meshes when drawing out a curve. this works great, however the scaling of the meshes is all over the place and i think i can narrow it down to the stretching of the meshes. as you can see in the attached image, the vertical element gets scaled up so if stretches the curve element.
what i want is that the elements are all the same size (as they are modeled).

i tried the stretching option in the brush modifier but it has 0 impact on this. am i doing something wrong? is this not working as its intended?
Screen Shot 04-30-18 at 02.41 PM.PNG

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Screen Shot 04-30-18 at 02.41 PM.PNG