Be sure to make the trap with a tinker of no more than 40 skill or the damage will be far too high!
Make sure you've got plenty of ingots and bolts because you will fail alot at the low level of tinkering, but its best because you don't want to kill yourself, just break the para.
Im about 28 tinkering and use a +20% tali which seems to keep the damage in the range of 7-10 and means I don't fail too often.
Its good to just get 8 boxes, trap them all, magic unlock them all, then store them so you can use them as and when.