Hey there. So I think this perk is pretty well balanced, adds a lot of flavor and doesn't need to be changed at all. That being said, I do think it could be improved slightly by doing this:
Remove the "standard" throwables from the list of items you create. By that I mean, caltrops, alchemist fire and choking powder.
Reasoning: The other throwables you create are awesome and truthfully, the only ones I end up using in serious combat. If we could increase the % that you make these by eliminating the standard throwables, I think it would add more flavor to the perk and limit the need to just toss stuff for no reason or directly into the trash. Of the three standards, choking powder is the most useful...but even so, the other things you create are far more effective and fun.
I suppose you can add thunderstone and acid flask to that list that could go too.
I'd like to see more of the EFU custom throwables around in general. There are only a few specific places you can get them. They're awesome but I barely ever use them because I only ever see them drop on the early quests.
I do think making the perk spawn only the custom efu throwables instead of the common ones that drop a lot or that you can buy in most shops, would be great for the perk!
Needs paint bombs.