If each clone source could have it's own blend mode (not to mention its own opacity and hardness) setting it would be more effective. The current blend mode setting in the clone source affects the preview only.
I often have to jump back and forth between Normal, Lighten, and Darken modes, and would like the convenience of clicking between sources already set to what I want.
What goes on in the new "Clone Source Panel" is unrelated to Tool Presets oddly. It would be possible, to optionally allow recording of the settings in the Panel, as part of the Clone Tool Presets. But they never bothered to do it. Its as if this feature was designed with no understanding of the importance of Tool Presets at all. This would solve your problem.
The shortcut for Lighten Darken and Normal are Alt > Shift > G, K and N, respectively. This may speed up your work.