Haven’t fished 6480 or 700h, but know they’ve got their fans out there. If the 6470 is a seeker, I’ve got that one and love it. Mines a G6470. 40lb bait or yoyo, lots of backbone, can still cast a bait. Just saw you need to fish 50 tho, so I’d go 700h.
It depends on what size line you are going to use and what you are going to fish for. If you are fishing bait for local school size tuna you could use the 6470 and fish 25lb or 30lb line. If you are fishing for bigger fish and using 40lb or even 50lb line you could use the 700H. I have caught Guadalupe YFT on a Fathom 30 two speed so you have a lot of options. The 6480 would be good when you have to cast a bait out past the seals. Bottom line is all three of the rods are good rods and could be paired with the Fathom 30 depending on what you want to catch. I would fill the reel with 50lb or 65lb spectra and then just change fluro leaders or mono topshots depending on what you want to fish for.
The 6470, 700H and 6480 are the basic go to rods for many San Diego anglers. I have 2 or 3 of each in the garage and use them all the time.