I am not sure as I never ran the panorama with refraction set to 0.25 as suggested by @chrislfa in this post.
This needs to be tested by generating panorama with 0.25, then twice running the wget command, once without &refraction=0.25 and again with &refraction=0.25 and see if there is any difference.
Yes. Simply issue the wget command again with the &alts=3048,12192 part at the end of command changed as required.
sudo wget -O /usr/share/dump1090-fa/html/upintheair.json "http://www.heywhatsthat.com/api/upintheair.json?id=XXXXXXXX&refraction=0.25&alts=3048,12192"
The argument -O immediately after wget results in overwriting the file upintheair.json, if it already exists.
Do NOT forget to reload your browser (Ctrl+F5) so that it uses the new file. If reload does not show new rings, clear browser cache (Ctrl+Shift+Delete) and then reload (Ctrl+F5).