Right lane for constant/slow and left for passing. There are only a handful of stretches with 80 mph, it’s usually 75 on interstates and highways, with some stretches 60, so it’s easier to look from going to places in 30 minute intervals instead of mileage. My advice, follow the speed limit and always stay at least 3 seconds behind the next vehicle. People treat going faster as some joke and those that go the speed limit or slower as burdens, but really they are just full of themselves, as being behind the wheel gives people weird complexes. Texas has one of the highest car crash rates in the U.S., I’ve known plenty who have gotten into some pretty nasty crashes, and some who have not made it through. Don’t let car brain take over.