I can see that there is a possibility to add two small free-rotating belt-tensioning pulleys on either side of the s/c pulley.
At leaset adding one on the left s/c (view from front) will make the whole installation a lot more logical.
It came to my mind as well, but did not know how to do it. If I understood you well, you said to add on the left side (pic view) to be fixed on SC and to be from outside part of belt, passive pulley.
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"They can order any color...as long as it is black"
H.F.