They work fine in pairs.
If the Roo weighs 5000 lbs, you have 2500 lbs on each side which is only 1250 lbs on each tire so weight capacity on the BAL is OK.
I have 2 BAL's and have used them both on one side. Our TT axles are very close together and they do fit.
They can be difficult to turn when loaded.
Keep the threaded rods well lubed.
I use them when I need less than 1" when leveling. When I need more than 1", I use blocks to level and then use the BAL's as chocks.
FOR SALE 2014 BOSS 6.2L F350
2012 Surveyor SV264