It sounds like you are asking more than one question here.
If you are trying to position a indicator based on a the sliders value, you can use the Position>>>Top property node to position your indicator on the front panel.
An interesting example (i believe it ships with LV) is called "Ghost in the machine".
The actual values you right to the position property will have to be adjusted based on your sliders position (see property >>>bounds) and its scale.
Just make sure you do not put the indicator on top of the slider otherwise you may have trouble grabbing it at run time.
Trying to help,
Ben