I had no trouble at all wrapping 4 to 6 inches of 6oz over the 3/4 radius of my cabin profile. The front radius of my roof profile is 13-1/2 inch.
Tony, I guess I get hung up on all of the reports by people who used epoxy on their bent roof plywood, w/o glass, and then suffered failure when the grain split open and water got in. Yours is the voice of experience, for sure.
I must be on my 3rd (maybe 4th) gallon of epoxy. I stopped buying quarts after about the 3rd or forth one; which came at about the same time there was a price increase. The gallons became much more economical, especially when factoring in the extra trips to the supply store.
My cabin is 9'-8" long, 64" wide and a tad over 4ft tall. I have applied two plies of 6oz most everywhere, roof, hatch, side walls, front wall, tongue box and wrapped under edges of the floor about 6 inches (before I am done I may still change my mind and do the whole underside of the floor). I must have at least 25 yards of 60 inch wide in it so far. Fortunately I can buy it locally; have had to make a few trips to resupply, plus had a few yards donated to me. I would start by buying at least 1 gal of epoxy right off the bat, but don't over stock because it does have a shelf life.
You will need more fairing filler than you think if you are going to use it to fill the cloth weave, especially if attempting to do it on vertical surfaces (they require thicker mixes to avoid sloughing off). After going through a few of the smaller canisters of the 410 I stepped up and bought the big can. Spraying a high build primer is another option.
I have used less of the bonding/filleting filler, maybe two small cans. I used PLP construction adhesive, not epoxy, for my wall and bulkhead to floor bonding; if I had used thickened epoxy for these joints I suppose it would have been more.