well i took them to get mounted yesterday and i was with the guy at the shop and measured what true center was, and idk if the measurement was exact but it seemed like it was wicked close to core center, so i just said fuck it and had him mount it core center, im just wondering what the actual difference is, it couldnt have been more than 1 cm though, but if i were you, i wouldnt go true center since its not a symmetrical ski, unless you just like center
Core center is the thinnest part of the sidecut (so the spot where the ski is at it's narrowest point), as well as the highest point of the profile (so where the ski is the thickest from base to topsheet). True center the the measured center of the ski (so measure tip to tail, divide by 2, there's your true center point). True center and Core center on most 100% symmetrical skis is the same point, on most other skis (directional/asymmetrical skis) it is two different spots. Most skis are marked with at least the core center of the ski, 90% of the time where it says "recommended" is the core center of the ski. Some skis are also marked with true center. However, it's not really the best idea to trust the chart on the topsheet because the topsheet graphic might be slightly off (sidewall markings are a bit more reliable, but still not always 100%). The best thing to do is to measure for yourself and mark it with masking tape and a marker before handing it over to the tech, this ensures you'll get it mounted exactly where you want it. To measure the true center point is the easier of the two, simply do what I said above, measure tip to tail, cut that measurement in half, then mark there. To measure the core center can be a bit trickier, the easier way to do it is to measure the markings on the ski (assuming there is a marking for both true and core center), measure from the core center line to the true center line (on the topsheet, not your markings), then use this to measure from the true center point towards the tail of the ski, there's your core center. The better and more exact way is to continuously measure the width of the ski (you can obviously guess to get a starting point so you're measure the whole ski) and find the thinest point, there's your core center.
As far as the difference for this exact ski, I believe core center is -2.5cms from true center, but I'm not positive on that (it's either -2.5 or -5...can't remember exactly, so it's better to do the measurements).