Tailwind for a marathon

Hello! Planning to use 4 bottles of water mixed with 4 packs of endurance fuel (so one standard packet of tailwind endurance fuel in each 500ml bottle) for my marathon fueling. I really like that the sodium and carbs are all together. I think I might throw in one of their caffeinated endurance fuel packs instead of the standard for my 3rd bottle. I’m hoping to complete the marathon in about 4:30/4:45. Thoughts about the fueling strategy? the only thing i was worried about is the 600ish mg of sodium per packet. is 2400 mg of sodium for a marathon way too much?