For example, If I wanted the player to have a higher chance (let's say 10%) of finding lock-picks/bobby-pins....

Basically I would like to "copy" the global effect of scrounger and also make a generic quest (like scrounger has) to change the chance for lockpicks if this lockpick perk is taken.

How would one, simply, copy the variable/scrounger effect and changing the loot tables?

Thanks in advance for any help/advice.

Scrounger works by having additional loot lists which get check for that perk. If you have the perk, then they have a chance of appearing in containers.

You can not "copy" the effect without constructing hundreds of new loot lists.