If you really want 2-in-1 preset options, you can use an AUX switch. A latching switch will snap to Toe or Heel ‘presets’ on alternate switch presses. A momentary switch will, of course, keep the Toe programming for as long as you hold down the switch. Heel / main preset on release.
Keep the Global setting at EXP, or EXP+AUX. Program your Heel & Toe extremes as you normally would (but with a switch, not a pedal). Pseudo-HotSwitch functionality, found in many H9 algorithms.
Now, the true morphing with an expression pedal “in one smooth gesture” … that’s where the real beauty lies here. Simple MIX adjustments, or bending space & time. And Lexicon Vortex-style, the cocked throw positions can be as interesting as either extreme.