Is there any possibility to have a float value for relative level control?
I am not sure if I'm understanding your question... But if you are meaning to have a fader from a touch panel return to you a floating point value - not 'out of the box'. You'll need to do some math in code.
for example: let's say you want to be able to go from zero to 100 but allow for one decimal place accuracy. 0.0 ~ 100.0 (or 1000 steps)
you'd need to create a fader with range 0 to 1000 and do the math when you get a level event. fp_MyLevel=type_cast(level.value)/10
You'll need the type_cast to avoid warnings on compile. I may have the wrong. I'm not at my computer right now to test. But, you'll probably need the type_cast in some way.
This is exactly what i did.