I spent some time with Ghom and elsewhere, testing some things. (I do not have Tasker and Theo).
I did not use any dps passives except when testing specific cases.
One interesting thing, is that when a sentry fires cluster arrow (and presumably other spenders), it will always crit for the same amount. This made testing easier.
+Sentry skill _does_ increase your hatred spenders' damage when fired by a sentry. I have a quiver that has +15 sentry skill. I have a different quiver with -3% damage compared to the first, with +15 cluster arrow skill.
When I switched quivers, cluster arrow crits went down a little. But if the +sentry skill had been ineffective, the +15 cluster arrow skill would have cause larger crits (as now there is +15% more damage).
Ambush and Steady Aim do in fact work for hatred spenders fired by sentrys.
***
Here's an important discovery that I have not found elsewhere:
After the first cycle of hatred spenders, sentrys will speed up according to your ias and whatnot. This is well known.
But each cycle still takes the same amount of time, regardless of IAS (apparently). I sat, listening to the cluster arrow shots until I counted 20 and measured the amount of time that took (48 seconds). (Elemental arrow bugs this by the way - don't use it).
This was the same whether I used a fast 1h xbow at around 1.7 attacks per second, or whether I used a slow 2h xbow at 1.1 attacks per second.
In either case, it took 48 seconds to fire 20 cluster arrow shots. However, the DAMAGE done by cluster arrow was proportional to the damage listed on the weapon. My 1h xbow(despite being more raw dps than my 2hxbow) did much less damage with the cluster arrows vs a 2h xbow.
Each cycle would be one cluster arrow, followed by one multishot, followed by 1 or more normal sentry shots (depending on weapon speed) follow by one more multi shot, then start over.
This probably explains my previous experience that seemed to feel as if 2h xbow was doing more damage using a sentry build.
