Dan,
That's correct. I will place jack stands under the frame to support the truck. That makes sense to use the jack to support the axle and unload everything. I want to be very cautious and not allow the springs to pop on me. That's a good call on the ratchet straps to add additional support for the brake lines/hoses.
Is there a proper order on removing the bolts for the springs? Front shackles? Rear shackles? U-bolts?