I had the same (maybe greater) internal
analysis paralysis RE: roof racks and platforms! Although I wrestled with DIY as well. I considered Gamiviti towers and DIY versions but fell in love with the backbone (not currently marketed for the 470). It's lower profile, to me it would spread load better than isolated paired towers; so I did my research and found the Prado 120 has a backbone in other markets and I worked with RR verify what we know, the prado 120 and GX470 are the same shell/roof.
I ended up with the Rhino-Rack backbone and pioneer platform on my 470. The backbone is widely available for the 460 and 5th gen 4R.
I like the RR platform's orientation longitudinal (front-rear) vs. front runner's transverse (side-side), but they look like almost identical platform pieces...

wide with one slot.
*edit*
With RR platform there are three steel U-channeled bars that mount at the roof mounts and spread platform load. the whole platform has 5 crossbars that fix to the front-rear platform slats, 3 of those five mount directly to the roof mounts (either towers/feet or where the backbone mounts to the roof)
*edit*
Rhino will be introducing a new platform this fall (per RR staff) that is a little lower profile, and has slots on the front and rear side bars AND slots in the underside....
I suspect many frontrunner accessories would work with the RR as the slots are standardized but Rhino offers a number of (pricey) accessories as well.
Here's current pioneer platform on a 5th gen 4r with backbone (76" platform)
Here's prototype next gen platform on a tundra. Note the different leading edge vs the taller straight leading edge in older/current style
I went 86" platform with fairing.
There's a still a little tweaking I'd like to try RE: fore-aft mounting and I want to see if removing the fairing would affect a noise change. It's fine now, but just curious... Some say without a fairing and allowing air to go over and under the platform, there's noise from turbulence generated under the tray because of the open U-channels which is alleviated with various filling solutions.... (80/20 extruded aluminum and various counterfits, have a rubber strip that would fit...
4th gen with ARB and the 120 platform with RR (RR sunseeker 2.5 is covering the platform though)