To keep it short I play on the dead march difficulty and I have notes that they are useless in the first have of the game. In addition, the payoff for making the superior potion and bombs is minimal. For that reason, I have rebalanced them.

For example:
For potions
Swallow - Toxicity from 20 to 15, Duration form 20 to 30. And ammo form 3 to 2
Swallow enchants - Toxicity from 20 to 10, Duration form 20to 35. And ammo form 4 to 4
Swallow superior - Toxicity from 20 to 10, Duration form 20to 40. And ammo form 5 to 6

For Bombs
Grapeshot – Damage from 350 to 300 and ammo form 2 to 2.
Grapeshot enchants - Damage from 600 to 600 and ammo form 3 to 4.
Grapeshot superior - Damage from 900 to 900 and ammo form 4 to 6.

HOW TO INSTALL
1. Extract the files to the The Witcher 3 Wild Hunt\content\patch0\bundles for GOG,
or to \Steam\SteamApps\common\ The Witcher 3 Wild Hunt\content\patch0\bundles for steam.
2. Run corresponding .bat file Potions_and_Bombs.bat.

HOW TO UNINSTALL
1. Run uninstall.bat