Sonic Barrier damping sheets vs cork


I want to dampen my Jolida J9 phono pre, and was wondering what would be the preferred material.
Sonic Barrier sheets from Parts Express or .125" sheets of cork?

markeetaux
Another choice is the lead weights sold at hobby shops and fish & tackle shops. Lead is an excellent damper, and possesses very high mass for it's volume. Pretty cheap, too.
No other comments, specifically about the merits of cork as a damping  material? 
I like cork quite a bit particularly around circuit boards and transformers. Lead not so much.
I have a friend (Pete Curry, bassist/recording engineer in Los Straitjackets) who put down a cork floor (over concrete) in his studio. Sounds pretty good---cuts down on reflections, but is not too dead. So Geoff, how come no likey lead as mass damper? I'm about to put some little stick-on lead weights (like for wheel balancing) on the counterweight of my pickup arm to increase it's mass (so's it can be closer to the arm's pivot, thereby lowering it's effective mass). No?