The OEM bars are what I have- plenty strong but they stick up much higher than I’d like. You need more than load bars, it’s the height of the towers that is the issue.
How many people are you planning to sleep? I have a full sized iKamper skycamp which has tons of room for my family and 1min setup, but if it was just 2 people I’d look at a lighter weight model like this 76lb one
Standard Lightweight Rooftop Tent - Inspired Overland
Hard shells are the only way to go- I started out with a soft shell tent and they’re a lot more work to setup, a lot more wind drag, and not as good in wind and rain.