You'll likely need more than one procedure, but the number of grafts you've been quoted would be a nice start for setting a foundation.
FUE is NOT scarless, this notion needs to be abandoned, all surgery leaves scar tissue, good surgeons mitigate it but the way your own physiology responds to scarring is out of a doctor's hands even when they're elite.
As far as FUT and FUE is concerned, in your case it will be about maximizing donor hair, which to be candid, lends itself to FUT over FUE if you're a Norwood 5.
Hair restoration is not appropriate for advanced hair loss if full coverage is your goal, it's why preventative treatment in tandem with a transplant is always recommended.
Your donor is finite and no transplant will ever be as full as your original hair, you're trusting an elite surgeon to create a cosmetic illusion of density and fullness, but nothing will ever match nature's original head of hair in terms of fullness.
Dr. Gabel is an empathetic surgeon, he'll shoot you straight too.
Ask him all these questions.