From what parameters of heroes in formation depends on the amount of gold obtained per unit of time when grinding offlie???

So, I get gold even if I close the game in an area where the mobs would kill me if I was online?

Nope! Level of zone to logout does not affect anything. E.g. you can go to lvl 1 zone and logout than after 30 min when you will open game again you will find not a few thousand of gold but q\Q\s\S\etc (depending on the max zone lvl).

So what i found by testing this theme myself:

*Zone lvl where you are going offline does no effect on gold grind amount.
*The Bush Whacker lvl and click damage does no effect too.
*Formations DPS does.
*Gold Bonus does.
**Dependence between [dps & gold bonus] and gold amount that you obtain by offline grinding is nonlinear.

Buffs was not tested.

I was testing online grinding and offline grinding with same formations each by 5 mins. I had at that time 102 zone maximum, at 101 zone with mine formation i was never died. So:
- From online grinding at zone 101 for 5 mins i've got 75.24s (from 6.06s to 81.3s)
- From offline grinding for 5 mins i've got 62s (from 91s to 153s).

So, conclusion is: online grinding is better than offline!

Emm... look at this: i was unlocked 104 zone without any hero upgrades and for 5 mins offline grinding i found 77s gold. So, if you want from 10-15 attempts unlock as much as possible zones and then go away for a long time - offline is better choice. But if you cant unlock 2-3 more zones than that on wich you never dies being online, better is online grinding!