a pretty simple question, assuming you are capable of killing all targets easy, which of these RES are most profitable? hazardous RES seem harder to come by.
That's a very good question. I keep switching from one to the other. The instances keep changing, so if I get a run of bad instances at the Haz RES, I switch to the HI RES, or the other way round. At times at the HI RES, I've had very high earnings rates, when there were lots of bad guys and even more Feds doing half the work for me. It makes dealing with wings of bad guys easier too. Sometimes, at the HI RES, there's no Feds, so it's just like the Haz RES.
Haz RES has one key advantage: If you accidentally tag an innocent ship to become wanted, nobody cares. You can stay there without any risk. After the 8 minutes has expired, you can log out and in again to remove your wanted status so that you can go back to the station to claim your bounties rather than jump to another system and back again. If you're unlucky enough to get a murder bounty, you can still stay at the Haz RES without risk, but the Feds will get you at the station unless you use stealth tactics or boost in and out, or you can claim your bounties at any outpost if there's one in that system.