Ok. There seems to be some confusion on terminology here. Not trying to talk down to you, but we should be clear about what we're discussing and make sure everybody is on the same page.
This is a hydraulic roller lifter for a 3.0 (which came stock in your Vulcan):
The roller rides on the cam lobes, and the base of the pushrod sits in the cup at the other end. When the cam spins, the lobes lift/lower the lifters and pushrods.
This is a roller rocker arm:
They sit on top of the cylinder heads and act like a teeter totter between the pushrod and the valves. So when the pushrod comes up, the arm pushes the valve down, opening the valve to let intake air or exhaust through.
Sounds like you have aftermarket roller rockers with a 1.8 ratio, right? Stock ratio was 1.6, so you should get quite a bit more valve lift with the new rockers, meaning the valves open farther. That also means that the valves travel faster, because they now cover more distance in the same amount of time. That adds stress to your valve springs, and the 3.0 isn't known for having strong springs anyway. Tom Morana (who was probably the original seller of your new rocker arms) also sells a valve spring upgrade. If you can get them, I'd highly recommend that. Otherwise you risk floating valves if the springs are not strong enough to keep the proper pressure on the rocker arm. That would limit your power upgrade. Even worse, it opens you up to breaking valve springs, which can happen even on stock 3.0s as they get into higher mileage. If you can get your hands on a valve spring upgrade then I would definitely do it. If you cannot, then I'd at least try to get new stock replacements.
I don't have any experience with adjustable rockers on the 3.0, but I do have Morana's standard 1.8 rockers and they've been fine. I would spin the engine by hand and carefully double check the roller tip where it meets the valve stem to make sure that it rides properly throughout it's range of motion. Other than that, I'd just make sure things are well lubricated and properly torqued. The install was pretty straight forward for mine. Obviously, you'll need to make sure yours are properly adjusted. I'm sure there are some good youtube videos on the topic that you can review.