I am really just learning about tungsten as shot alternative (Thanks Jerry), even though for many years knew military used tungsten in certain rounds, but that is for a single projectile. Anyway I am not wanting to sound like some expert since clearly not but my understanding based on work of others is that the Hevi-X was designed to be for waterfowl use and is suppose to replace steel but only be comparable to lead shot at about a density of 12.
The name of the game is density, but guessing the performance Jerry is seeking with the smaller shot he is using suggests a density of about 18. I think Hevi-shot now a trademark did try and make a turkey load with some tungsten that was suppose to have a density of 13. Here is link to shotgun world discussion. Personally I don't like to attach links to much to other forums or discussions, but this discussion may prove helpful, assuming information they provided is correct.
http://www.shotgunworld.com/bbs/viewtopic.php?t=459367
Btw; Jerry thank you for your work on this tungsten notion. Now I'm having a shot inferiority complex, just like cooleritus virus that I got when Yeti came out. I am now calling it tungstenitus and both can result to the dreaded procedure of a required cashectomy.
Like some surgeries alot of them are unnecessary.