Absolutely, that part is easy!
Code:
SliderLeft.init(DETAIL_SLIDER_LEFT_XSTART, DETAIL_SLIDER_LEFT_YSTART, DETAIL_SLIDER_LEFT_YSIZE,
DETAIL_SLIDER_SCALE_LOW, DETAIL_SLIDER_SCALE_HIGH, DETAIL_SLIDER_SCALE, DETAIL_SLIDER_SNAP,
DETAIL_SLIDER_SLIDER_COLOUR, DETAIL_SLIDER_BG_COLOUR, DETAIL_SLIDER_HANDLE_COLOUR);
SliderLeft.draw(LevelLeft);
I suppose you'll need something a bit more useful though, right? 
Code:
SliderLeft.init(125, 101, 100, 0 2, 0.4, 0.2, ILI9341_DARKGREY, ILI9341_BLACK, ILI9341_GREEN);
SliderLeft.draw(LevelLeft);
I don't use setScale() outside of the init.
I am debating moving to the bar graph option instead of the slider. I initially wanted to be able to grab the handle and move it but now I'm reconsidering. I do love the look of the slider...so we'll see!
Thanks!