Hi MC,
You’ve already had a great response to your question which should validate your wise choice of String Brand. As per your Short Scale OM; your thinking is accurate; shorter scale equals less tension. Indexless should have settled any fears that the low tension set might be too low. As to what to expect with Mid-Tension strings on the same guitar; you will enjoy increased volume with a corresponding feel in string tension. It’s a pretty cheap and reversable experiment to try both styles on your OM to determine what suits you best. One caveat: you may sometimes want to adjust your truss rod and/or saddle height to maintain the same action in response to the difference in overall tension between the two string categories. Thank you!
Best, Richard