I'm trying to figure out what procs to put on my weapons as a Shadowblade.. i want procs that are good vs other stealthers, but cant seem to find the info on the forum. Any suggestions to webbies that have that info (and also applies to uthgard server) ?

Armor does not have elemental weaknesses at this patch level. So it doesn't matter what armor type they are using.
So the only thing that impacts your proc damage will be resists levels within the enemies template.
Assuming all enemies are fully templated it really doesn't matter which damage type you use - use the one that looks best (heat, ofc).

However, and this is particularly true with stealthers, often certain resists are left uncapped since they are notoriously expensive to fully template.

I'm not sure if this is accurate, and i would advise doing some additional research but if i remember correctly it's typically:

Mid - tend to lower matter if required.
Alb - tend to lower spirit if required.
Hib - tend to lower heat if required.
*somebody please correct me if i'm wrong here.

Obviously some people can (and do) reduce all resists by a % point or two rather than reduce one by 10-15. Some people are aware that stealthers think this way and cap the off-resists just because they are aware that procs often get used for the off dmg types.

TLDR:
If you enemy is well equipped, it doesn't matter.
If your enemy has put some thought into their template, there is no guarantee the dmg type you choose will be the best one.

You may also want to look at and consider racial resist bonuses for your most common enemy races.

Best bet is to probably have different proc dmg types on your different weapons so as to give you the best scope for finding a weakness.