The best way to test them is to get a set of Eneloops, the standard 2000mAh cells are fine. Run a refresh on them in your BC1000 and record the capacity. Then fully discharge them (you can use the BC1000 for this), you will have to monitor them, have a timer running. You can use this discharge calculator,
http://www.powerstream.com/battery-run-time-calculator.htm
to find out the time it will take the cells to discharge. I would round it off with the lowest capacity cell, ie: a cell at 1958mah i would pick 1900mAh just so you can catch that cell just in case it starts charging again. Then once all the cells are fully discharged (1.20v resting charge) recharge them in your sunlabz charger. Then do another refresh in the BC1000. Choose refresh because i think if you simply do discharge the charger won't keep the discharge data in the display. So you'll need to time it again before it discharges the cell again and you could get a bigger reading. If the cells read lower than your initial capacity (like off more than 100mAh) chances are your Sunlabz charger undercharges them. If the capacity reading is 100mAh higher then it could be overcharging the cells. Then again from that test it's still hard to tell. Another good way of testing this is how long the cells are charging in the La Crosse versus the Sunlabz. You can use this calculator to estimate the charge time as well,
http://www.csgnetwork.com/batterychgcalc.html