Interesting. It has been a couple of years, so I guess Lippert has killed the name?
Tweetys has also been pretty reasonable for stuff in the past and shipping was pretty quick.
Doing one side at a time is going to be a lot harder. What happens is that when you drop one side of the axle it puts things in a bind and trying to get them lined back up is a real pain in the neck. Don't ask me how I know (LOL). BTDT. It is far better if you can to completely support the trailer, remove all 4 tires and drop everything as one package. If that is not going to happen, then you must have some sort of pry bars. I have a couple with a point on one end, like a drift that used to force the springs back into position.
Send me a PM and I will be glad to talk to further. If you want to talk in person, PM me your phone number and I can talk you through the process.