The masts are only six inches thinner than the one on the real Agamemnon.
Six inches may not sound like a lot, but take my word for it, it is. Before the economy went kerflooie I was a steel worker, building hydrogen plants, and let me tell you, when working with steel pipes ranging from ½" up to 36", there is a major difference in even 1 or 2" difference in size. There is only 5" difference between a 3" pipe and an 8" pipe, but size and strength wise, they are miles apart. At the scale we are working at here, those masts may as well be bamboo sticks for all the support they would give. I doubt they could support those large fighting tops the way they are drawn in drydock on a windless day, let alone at sea in even a moderate swell.
And the cutters are behind the pinnace.
There may not be room between the pinnace and the funnel for the cutters, unless your ship has a significantly wider beam than suspected. Either that or you have kayaks for cutters.