I found the TB54 version for sale and after some measuring it will work for me. IIRC this is the one recommended for steel, correct? I assume i can simply through bolt these as well?
the TB 54 is the same as the TB60, it is just shorter (54" instead of 60"). They might come with flare nuts as i'm not sure that Thule sells the TB 54's with the nuts and bolts that you'll want to use for a fiberglass installation. You'll want the fiberglass option b/c it will come with all the associated hardware for a bolt through design that you can put a nut on the back end of. IMO i would get the TB60s for fiberglass and that way you wont need to source all the little nylon washers, bolts, cap nuts ect. it just makes the installation easier. Also you can cut these down if you wanted. the end caps just slide in so its not a big deal to get the 60's and make them 54's
Also, how can i ID the 460 vs the 430's? Are they a different height where the two cant be used together? I would need more than two Loadbars under my Overland 1.8.
the Podium 460's are a much better design in my opinion for carry a tent on a trailer. the design of the 460 is such that it is a 1 piece design that once attached to the rail has no secondary piece that snaps on and off. This gives it much more strength and allows it to handle the tent more securely. additionally, the 460 is much easier to work with when setting up for equal distance on the bar as it will not shimmy up the load bar as it is tightened.
the benefit of the 430 is that they snap on and off easily which for me wasn't an issue b/c my tent will stay on my trailer all the time. On my jeep for carrying snowboards i use the 430's. the weight of the snowboards is minimal and i like to remove the bars once i get back and not have them sitting up on my roof while i drive the car around. this however is also its weakness IMO of the 430's b/c the connection is not as secure. on a washboard road at 25 i dont want my tent to come flying off my trailer. I know they have been used for years by AT to hold their tents but the 460 is the replacement for the 430 and works much better IMO.
i would not use the 2 together, they are different heights (off by a small amount but different enough to maybe cause an issue). as for loadbars, i only needed 2 with my eezi awn 1200 but now need 3 with my globetrotter. I would say if your 1.8 is around the size of a eezi awn 1600 or smaller you could probably just use 2, if its larger then you'll definitely need 3 IMO.