Alright boys I've made some important discoveries.
For testing purposes I respecced Jubilost into Grenadier 2/Arcane Bomber 4 and I noticed a few things:
- Precise Bombs discovery works with Arcane Bombs.
- Bombardier's Utility Belt and the feat Extra Bombs only increases the Alchemist's bomb uses per day, so it doesn't double dip.
- BOTH the Alchemist's bombs and Arcane Bombs damage scales with levels into Arcane Bomber. At Grenadier 2/Arcane Bomber 2 the bombs start doing 2d6 damage.
- Acerbic Ring double dips with Arcane Bombs, 1 ring increases the damage of Arcane Bombs by 2d6, 2 increase it by 4d6. While Alchemist's Bombs only get a 1d6 increase.
- Sneak attack works with Bombs on the main target. 5d6 damage late game with Sense Vitals
There are a lot of posts that say Precise Bombs doesn't work with Arcane Bombs, but it looks like it does. Keep in mind that I took the 2 Grenadier levels first, then the Arcane Bomber levels, so maybe it doesn't work the other way around. I took the Acid Bombs discovery with Grenadier and acid damage with Arcane Bombs,
maybe that's why Acerbic Ring double dips, who knows, I don't care enough to test other damage types. Arcane Bombs double dip even if you take Choking Bombs.
This makes Grenaider 2/Arcane Bomber 18 a very strong build IMO. At lvl 4 with 18 Int you have 12 Acid Bombs(same level Alchemist has 8 at this point) that deal 2d6+Int damage. Every level nets you more uses and scales damage. Not only that but you're a Wizard with level 9 spells that can specialize into Conjuration early and into another school later, maybe Necromancy. Profane staff is also a good idea.
Goddamn it, now I'll have to restart my playthrough again.
Edit: You can also take Choking Bombs at lvl 2 instead of Acid Bombs for even more control and less damage. Definitely a thing to consider.
Edit2: Target reflex with Grease and fortitude with Choking Bombs.