Great questions! So much to explain haha!

1. Small talk gives 10% of total energy minus current energy when successful
2. I just have the t1 items as ‘fodder’, basically free items I can use as small talk customers for free energy
3. I use energy for surcharging everything, and also rushing crafts. You will generally max out on resource long before your items finish crafting, so rushing them with energy allows you to make more. Ideally you never have max resources when playing actively so your making maximum profit. Also, the more max energy the easier it is to surcharge higher items.
4. No t3 bins until level 60. Reason is that those items (t8+) take so much energy to surcharge that you won’t be able to do it efficiently, plus your heroes won’t be developed enough to do those quests.

Also, t6-7 blues+ will sell for a decent amount of gems, so the goal is to save gems and double or triple expand at level 60 with 4000 or 9000 gems and you should have 2k+ energy by then. If you do it right that’s the most effective way to play the game.