One of my new favorite cooking techniques is to brown the chicken thigh first before slow cooking (as discovered doing the apricot chicken a few weeks back). Trying it with Japanese curry tonight. Recipe I read said 6 hours on low, but you wouldn't do the apple/potato/carrot that long would you? I was thinking 3-4 hours max.
I've been making japanese curry in a regular stove top pot. I just fry the meat separately to get a nice brown sear and throw it in with the veggies and some seasoning. Once the potatoes cook through, i chuck in the curry blocks.
I've thrown a veg/lentil curry in the slow cooker in the morning on low, gone to work, and come home 8 or 9 hours later and it's fine. Veg doesn't need that long but it doesn't seem to do much harm.
I only ever use high on my slow cooker then I'll turn it down to low if I need to. I'd put them all in together. If you're worried about the chicken drying out, dont worry it won't. Potato can take forever to cook particularly if you choose to cook it on low.
Low - approx 94°c
High - approx 149°c
Actually I'd leave the potato out and boil it separately and add it in later then you'll know it's cooked for sure.
I didnt factor in how cold the carrot and potato would be in reducing the temp so I've cranked it to high just before i put the veg in. I might just leave it on high and see how we go.