Jan Glete's assumptions about calculating Dutch and English sailing warship displacements

Jan Glete is an acknowledged expert on sailing warships. I have found his two-volume work, Navies and Nations to be very helpful in my research. His bibliography and notes are comprehensive. A key aspect in his work is comparison of navies by displacement. To do that, he developed a system for estimating displacements.

Jan Glete assumed, for various reasons, that English ships had finer lines than Dutch ships. My impression is that Ab Hoving agrees with that. When he designed the lines for the new Zeven Proviniën, he gave her very full lines. Jan Glete made the following assumptions:

Even in the 1650's Dutch ships were heavily armed, mainly with iron guns, which were heavier than brass guns.

The Danish and Swedish navies found ships built by Dutch design principles to be slower than ships built using English design principles.

The French found that English prizes sailed better than Dutch prizes.

English ship design methods required finer lines than more boxlike Dutch lines. Ab Hoving's book about Nicolaes Witsen illustrates this.

In retrospect, Jan Glete wonders if the difference might not be so great. He also now thinks that Dutch drafts might be greater than he had previously thought.