I clip or tape the mic cable to the mic stand at several points so that if the elastic breaks or the shock mount fittings become loose and cause the mic to fall off the stand it does not hit the floor.

Some shock mounts are more expensive than some of the bottom end large diaphragm mics...you get what you pay for. There is new generation shock mounts that will fit most sizes of mic but they tend to be expensive.
Here is a link to a couples of universal mounts which are pretty good
http://cgi.ebay.com/Mic-Small-Unive..._DefaultDomain_0&hash=item43a3c533bf

http://cgi.ebay.com/MXL-USM-001-Uni..._DefaultDomain_0&hash=item4aa889794c

http://www.soundclick.com/bands/songInfo.cfm?bandID=687727&songID=5238055