I only have experience with Dobinsons and have them on both my landcruisers. They are great and the oldest set which is 5 years old have not sagged and still hold a load well.
However ,I dont think you will be disappointed in the other 2 brands either.
In case you didnt know,the rears on a 71 are the same as a 60 series EDIT I just realized its an 07 so it may not be the same rears as a 60
You wont need the biggest spring packs available as these are heavy duty springs for 60 series ,which is 200 kg heavier