I'm sure you're done now but I've always used the tall jackstands under the frame on each side and then used my floorjack to hold the pumpkin up. That way you can manuever the axle where you need it. I've never re-used the ubolts either. I've always cut them off and then bolted on new ones with blocks/leaf springs. Much easier than unbolting them. It's already a pain to torque them down without air tools.
By the way never said it was safe