Join Date: Sep 2007
Location: Washington State
Honestly, I think it is very important to have a saddle that fits the horse well from the get go. I do understand financial challenges, but used saddles can often be found for a good price. Better to spend your money on a long term permanent fix as opposed to a quick fix.
That said, if I had to choose one of the wither relief pads and had no other option, I would either go for the fourth one or the last one that you've listed. You want to retain some amount of breatheability, so avoid things like gel and stiff foams. Look for things like open-cell foam.