I would not recommend a peak charger for the formation charge. Use the wall wart. Even on the big packs, just do hte numbers.

Red may disagree but I have seen that 1/10 fromation charge is a "fastest" recommended number. I have had very good luck doing formation charges at lower rates for longer periods. I formed a set of 1100 MAh NiMh cells at 50 MAH for 30 hours, discharge to .9V/cell, then another 30 hours. Those packs are working very nicely and take a full charge on the peak charger at 200 MAh charge rate on my Triton.