I am curious as to how all these fluits were employed

This document that I have, from the Admiralty of Rotterdam, dated 7 March 1652, has the list of warships in service, with dimension, guns, and captain listed, the fishery protection ships, not listed by name or captain, but with dimensions and number of guns, and then a long list of fluits, with captain, dimensions, and numbers of guns. One of the ships listed was the Blompot, the ammunition fluit commanded by schipper Coolbrandt. There are many others in the list, such as the Wassende Maen. All dimensions are in Maas feet, rather than Amsterdam feet. Many have the ship name listed, but they often do not. The Wassende Maen was large enough, and well-armed enough to be suitable as a warship, although the deck height was rather low:

The fluit ship Wassende Maen, of Claes Fuddinckburgh
Dimensions:
Maas feet:  112-1/2ft x 22-1/2ft x 9-1/2ft x 4-1/2ft
Amsterdam feet: 122ft-8in x 24ft-6in x 10ft-4in x 4ft-10in

26 guns

Sources:

1. lijst van oorlogh schepen der Admiraliteit te Rotterdam, 7 March 1652