How do they stack?
I know they’re next to useless in most situations, but I’m curious if anybody knows how they add time. Is it multiplicative or additive?
I also read that to get the bonus, you must have the shield and have it active. You also must have the pistol in your hand. It doesn’t count if you have 4 of them “equipped”?
I’m not sure bout that. I nether used both of these items 
I believe it’s additive. The veritas must be in your hand for it to work. Simply having veritas in all 4 weapon slots will not help. In that regard, it would be like having the aequitas but in your backpack and not in the slot.
However, it would be interesting to note if you would get the veritas’ bonus twice if gunzerking with two.
For extra fun, equip the Sheriff/Deputy badges and play as Krieg with Redeem the Soul, and everyone having both the varitas and aequitas equipped, of course.