@dcg141 i recall the same issue two years ago when I was researching the front Bilstein 6112s coilovers that came with my gx470. These are the 2.5” diameter shocks with the beefier shaft.
Bilstein didnt list the GX470, but had the V6 4R, V8 4R and the FJC listed as separate part numbers. Mine turned out to be the FJC ones with 600#/in springs. I put the details somewhere on my build thread.
I have no additional weight up front (all stock) other than bigger tires and aluminum skid plates, but it rides real smooth up front.
If I were to add weight up front like a hidden winch tray and winch, I would probably need the 650#/in coils. Maybe 700#/in if you also get a new front bumper with a winch and second battery.