You could try putting tape around the pipe to make it fit tighter in the floor socket. Add a third leg to make a 'tripod' support system, or add 'outriggers' to the pipe, sort of an upside down spread 'U' to the pipe to keep it from wobbling. My dad did the 'outrigger' thing to a table on a boat we had. Made it out of mahogany board, it had two through bolts attaching it to the pipe. The feet were about 6 inches out to each side and touched the deck when the pipe bottomed in the socket. Added great stability and keep the pipes from rolling when stowed away.
Bob & Donna
'98 Gulf Stream Sun Voyager DP being pushed by a '00 Beetle TDI