I love the Suntour shifters. I’ve tried them stem mounted but was not really happy no matter where I mounted them. I believe the problem for me is that they are mounted too far rearward from the axis of the stem. I believe that is the reason for the easy use of the great Schwinn Twin Stik levers as they are mounted forward of the stem axis. I think the forward mounting allows the hand to subconsciously bump into the handlebar stem and automatically find the levers. IIRC, I believe I once looked at the Suntours to see if they could be reversed to be positioned in front of the axis vs behind. I run them on down tubes now after trying stem mounts at several different heights. YMMV of course and with Suntour ratchets, you can’t go wrong.