If I understand your post, you are using soft cuttings with most of the foliage removed, stuck in a seed tray with hormone, on a heat mat. You mention a heat mat promoting humidity, and in my experience it does the opposite, that is it dries the moisture from the mix. Do you have a clear plastic tent, or cover to keep the air around the cuttings close to 100% humidity? You don't mention a mist system so I presume you do not have one. These should grow roots in about a month if you are able to control the humidity, the mix temperature and moisture. If using a tent or cover it should be removed at intervals to remove excess moisture and provide air and oxygen. I was not able to see your picture. Al

That's correct I am using soft cuttings with most of the foliage removed, Seed tray/hormone on a heat mat. With a plastic hot house cover to keep the humidity in. I have been removing the cover every other day to give it fresh air and have a simple lamp nearby to live it light.

When the water at the bottom of the tray is all evaporated should I add more or leave it be?