I have to mount 18K BTU AC-only line sets at two locations on Certainteed/Vytec simulated polymer cedar split shake called Cedar Impressions or Rough Split Shakes.

http://www.certainteed.com/resources/CTS100.pdf

Due to the placement of the compressors, each requires horizontal and vertical runs but I have options as to which stage is vertical or horizontal. I can go up an inside or outside corner post to the then run horizontally to the line set penetration or I can go along a sill-level PVC trim mud board (lower frieze board) and then climb vertically up the shingles directly under hole.

Aesthetically the vertical run directly under the mini-split hole looks better but that means running the line hide up the irregular elevations of the shakes (bevelled faces like clapboard but even more complex with the uneven face planes and elevations of each course).

Any suggestions on how to run these hides so they fit in with the siding profile? I don’t much like seeing air behind a wall mounted post. I have a box of black PVC 1 X 8″ trim boards in my shed.

And would it be better to paint the line covers the same color as the shakes or create contrast by making them the same as the trim (dark grey shakes, black trim).

Any recommendations on line hide brand? They are so expensive, I want to make sure I select the one the stands up best to UV and assembles the tightest.